Alpha Numeric: Level 3
1.
In the correctly solved addition `ABC + CBA = 1332`, A, B, and C represent distinct digits. What is the digit B?
Solution (D):
1. Units: \(C+A = 2\) or \(C+A = 12\).
2. Hundreds: \(A+C + (\text{carry from tens}) = 13\).
3. Since \(A+C\) must be 12 (or 11), \(C+A=2\) is impossible (as A, C must be non-zero for 3-digit numbers).
4. So, Units: \(C+A = 12\). (Carry a 1).
5. Tens: \(B+B + 1 = 3\) or \(B+B+1 = 13\).
6. If \(2B+1=3\), \(2B=2 \implies B=1\). (No carry to hundreds). Hundreds would be \(A+C+0 = 12\). This is consistent.
7. If \(2B+1=13\), \(2B=12 \implies B=6\). (Carry 1 to hundreds). Hundreds would be \(A+C+1 = 13 \implies A+C=12\). This is also consistent.
8. We must check “distinct digits”.
If B=1, A+C=12. Possible (A,C) pairs: (3,9), (4,8), (5,7). All are distinct from B=1.
If B=6, A+C=12. Possible (A,C) pairs: (3,9), (4,8), (5,7). The digits must be distinct from B=6. All pairs are valid.
*Correction:* Let’s re-read the image. Q1 `XYZ + ZYX = 848`. My question is different.
Ah, I see `A+A = CB` and `C+B=5` (Q7). Let’s use that logic.
If \(B=1\), A,C can be (3,9). e.g., 319+913 = 1232. Not 1332.
If \(B=6\), A,C can be (3,9). e.g., 369+963 = 1332. This works.
So B must be 6.
2.
In the problem `A + A = CB` and `C + B = 5`, A, B, and C are distinct non-zero digits. What is the value of A?
Solution (B):
1. From `A+A = CB`, \(2A\) is a 2-digit number `10C + B`.
2. Since A is a digit, the largest `2A` can be is 18 (if A=9). This means the tens digit, C, must be 1.
3. From `C+B = 5`, if \(C=1\), then \(1+B=5 \implies B=4\).
4. Now use `2A = 10C + B`.
5. \(2A = 10(1) + 4 \implies 2A = 14 \implies A = 7\).
6. The digits are A=7, B=4, C=1. They are distinct and non-zero. This is the solution.
3.
In the multiplication `AA \times A = 39A`, A is a non-zero digit. What is A?
Solution (A):
1. `AA` is \(11 \times A\). The equation is \((11 \times A) \times A = 39A\).
2. \(11 \times A^2 = 390 + A\).
3. We can test the options.
(A) \(A=6\): \(11 \times (6^2) = 11 \times 36 = 396\). \(390+A = 390+6 = 396\). This matches.
(B) \(A=5\): \(11 \times (5^2) = 11 \times 25 = 275\). \(390+5 = 395\). (No).
(C) \(A=7\): \(11 \times (7^2) = 11 \times 49 = 539\). \(390+7 = 397\). (No).
4.
In `XYZ + ZYX = 998`, X, Y, and Z are distinct digits. What is Y?
Solution (C):
1. Units: \(Z+X = 8\) or \(Z+X = 18\).
2. Tens: \(Y+Y + (\text{carry}) = 9\) or \(19\).
3. Hundreds: \(X+Z + (\text{carry}) = 9\).
4. From Tens: \(2Y + \text{carry}\) must be odd. Since \(2Y\) is even, the carry from the units *must be 1*.
5. This means from Units: \(Z+X = 18\). (The only pair is 9,9, but they must be distinct. This is a contradiction).
*Rethink:*
Let’s re-check Tens. \(2Y + \text{carry} = 9\) or \(19\).
*Case 1:* Carry from units = 0. Then \(Z+X = 8\).
Tens: \(2Y+0 = 9\) (impossible) or \(2Y+0 = 19\) (impossible).
*Case 2:* Carry from units = 1. Then \(Z+X = 18\). (So X=9, Z=9).
But X and Z must be distinct.
*Rethink again:*
1. Units: \(Z+X=8\) (no carry) or \(Z+X=18\) (carry 1).
2. Tens: \(Y+Y = 9\) (no carry) or \(Y+Y=19\) (no carry) or \(Y+Y+1=9\) (carry 1) or \(Y+Y+1=19\) (carry 1).
3. `2Y=9` (no), `2Y=19` (no).
4. `2Y+1=9 \implies 2Y=8 \implies Y=4\). (This implies carry from units=1).
5. `2Y+1=19 \implies 2Y=18 \implies Y=9\). (This implies carry from units=1).
This is complex. Let’s restart.
Units: \(Z+X = 8\) (carry 0) or \(Z+X = 18\) (carry 1).
Tens: \(Y+Y = 9\) (carry 0) or `… = 19` (carry 1) …
`2Y + \text{carry}_1 = 9 \text{ or } 19`.
Hundreds: \(X+Z + \text{carry}_2 = 9\).
From Tens: \(2Y + \text{carry}_1\) must be 9 or 19.
If `carry_1 = 0` (from units): `2Y=9` (no) or `2Y=19` (no).
If `carry_1 = 1` (from units): `2Y+1=9 \implies Y=4` (carry_2=0) OR `2Y+1=19 \implies Y=9` (carry_2=1).
So, we must have `carry_1 = 1`, which means \(Z+X=18\). This means \(Z=9, X=9\). But they must be distinct.
This implies my analysis of Q5 in the L3 brainstorming was wrong.
`XYZ + ZYX = 998`.
Units: `X+Z=8` or 18.
Tens: `Y+Y = 9` (if no carry) or `Y+Y+1 = 9` (if carry). OR `Y+Y=19` or `Y+Y+1=19`.
`2Y=9` (no). `2Y=19` (no).
`2Y+1=9 \implies 2Y=8 \implies Y=4`. This means carry from units=1.
`2Y+1=19 \implies 2Y=18 \implies Y=9`. This means carry from units=1.
*Contradiction!*
If Y=4, carry from units must be 1. So `X+Z=18`. `X=9, Z=9`. Not distinct.
If Y=9, carry from units must be 1. So `X+Z=18`. `X=9, Z=9`. Not distinct.
This question has no solution with distinct digits.
Let’s re-use Q1 from the L3 brainstorming. `ABC + CBA = 1332`.
Units: C+A = 12 (carry 1)
Tens: B+B+1 = 3 (carry 0) or B+B+1 = 13 (carry 1)
Hundreds: A+C + (carry) = 13
Case 1: `2B+1=3 \implies B=1`. Carry=0. Hundreds: `A+C+0=13`. Contradicts `A+C=12`.
Case 2: `2B+1=13 \implies B=6`. Carry=1. Hundreds: `A+C+1=13 \implies A+C=12`.
This is consistent. Solution is `B=6`, `A+C=12`.
Question: What is `A+B+C`?
`A+B+C = (A+C) + B = 12 + 6 = 18`.
4.
In `ABC + CBA = 1332`, A, B, and C are distinct non-zero digits. What is \(A+B+C\)?
Solution (D):
1. Units: \(C+A = 12\). (Must be 12, not 2, to get 1332. Carry 1).
2. Tens: \(B+B+1 = 3\) or \(B+B+1 = 13\).
3. Hundreds: \(A+C + (\text{carry from tens}) = 13\).
4. Case 1: Tens sum to 3. \(2B+1=3 \implies 2B=2 \implies B=1\). (Carry 0).
Hundreds: \(A+C+0 = 13 \implies A+C=13\). This contradicts \(A+C=12\).
5. Case 2: Tens sum to 13. \(2B+1=13 \implies 2B=12 \implies B=6\). (Carry 1).
Hundreds: \(A+C+1 = 13 \implies A+C=12\). This matches the units column.
6. Solution: \(B=6\) and \(A+C=12\). The digits must be distinct. e.g., A=4, C=8, B=6. (468 + 864 = 1332).
7. Sum: \(A+B+C = (A+C) + B = 12 + 6 = 18\).
5.
The 5-digit number `7A,5B2` is divisible by 4 and 9. A and B are distinct digits. What is the largest possible value of \(A+B\)?
Solution (D):
1. Divisible by 4: The last two digits, `B2`, must be a multiple of 4.
Possible `B2`: 12, 32, 52, 72, 92. So \(B\) can be {1, 3, 5, 7, 9}.
2. Divisible by 9: Sum of digits must be a multiple of 9.
Sum = \(7+A+5+B+2 = 14+A+B\).
3. Test cases for B:
– If \(B=1\), Sum = \(15+A\). \(A=3\) (sum 18). \(A+B = 4\).
– If \(B=3\), Sum = \(17+A\). \(A=1\) (sum 18). \(A+B = 4\).
– If \(B=5\), Sum = \(19+A\). \(A=8\) (sum 27). \(A+B = 13\).
– If \(B=7\), Sum = \(21+A\). \(A=6\) (sum 27). \(A+B = 13\).
– If \(B=9\), Sum = \(23+A\). \(A=4\) (sum 27). \(A+B = 13\).
The largest possible value for \(A+B\) is 13.
6.
In `AA \times B = CBC`, A, B, and C are distinct non-zero digits. What is A?
Solution (A):
1. `AA * B = (11*A) * B = 11AB`.
2. `CBC = 101C + 10B`.
3. `11AB = 101C + 10B`.
4. `11AB – 10B = 101C \implies B(11A – 10) = 101C`.
5. Since 101 is prime, one of the terms on the left must be a multiple of 101.
6. `B` is a single digit, so it can’t be.
7. `(11A – 10)` must be a multiple of 101.
8. Test A: If \(A=1\), \(11-10=1\). If \(A=9\), \(11(9)-10 = 99-10 = 89\).
*Rethink:* My logic `B(11A-10) = 101C` is correct.
If `A=9`, `B(89) = 101C`. Since 89 and 101 are prime, this can’t be true unless B=101 or A=101.
*Rethink:* Let’s test `A=9`. `11 \times 9 \times B = 99B`.
`99B = 101C + 10B \implies 89B = 101C`.
Since 89 and 101 are prime, this only holds if `B=101` and `C=89`. Not possible.
Let’s re-use the *other* puzzle I made. `AA \times AA = ABA` (from image).
\(A=1 \implies 11 \times 11 = 121\).
This fits `ABA`! \(A=1, B=2\).
Question: A+B? Answer: 3.
6.
In `AA \times AA = ABA`, A and B are distinct digits. What is \(A+B\)?
Solution (C): This is from image 8.
We test values for A.
If \(A=1\): `11 x 11 = 121`. This fits the pattern `ABA` where \(A=1\) and \(B=2\).
A and B are distinct (1 and 2).
The value of \(A+B\) is \(1+2 = 3\).
If \(A=2\): `22 x 22 = 484`. `ABA` would be `2B2`. This does not match.
7.
In `A7 \times B = 3C2`, A, B, and C are distinct digits. What is A?
Solution (B):
1. Look at the units: \(7 \times B\) must end in 2.
2. Test values for B: \(7 \times 1 = 7\), \(7 \times 2 = 14\), \(7 \times 3 = 21\), \(7 \times 4 = 28\), \(7 \times 5 = 35\), \(7 \times 6 = 42\).
3. The only digit that works is \(B = 6\).
4. The problem is now `A7 \times 6 = 3C2`. The result is in the 300s.
5. Test values for A:
If \(A=4\): \(47 \times 6 = 282\). (Too small).
If \(A=5\): \(57 \times 6 = 342\). This fits the pattern `3C2`, with \(C=4\).
If \(A=6\): \(67 \times 6 = 402\). (Too large).
6. The only solution is \(A=5, B=6, C=4\). They are distinct.
The digit A is 5.
8.
The 5-digit number `35,X7X` is divisible by 18. What is the digit X?
Solution (D):
1. Divisible by 18 means divisible by 2 AND 9.
2. Divisible by 2: The last digit, X, must be even. X can be {0, 2, 4, 6, 8}.
3. Divisible by 9: The sum of digits `3+5+X+7+X = 15+2X` must be a multiple of 9.
4. Test the even X values:
– \(X=0\): \(15 + 2(0) = 15\). (Not a multiple of 9).
– \(X=2\): \(15 + 2(2) = 19\). (Not a multiple of 9).
– \(X=4\): \(15 + 2(4) = 23\). (Not a multiple of 9).
– \(X=6\): \(15 + 2(6) = 15 + 12 = 27\). (This is a multiple of 9).
– \(X=8\): \(15 + 2(8) = 15 + 16 = 31\). (Not a multiple of 9).
The only solution is \(X=6\).
9.
In `XYZ + ZYX = 848`, X, Y, and Z represent distinct digits. What is \(X+Y+Z\)?
Solution (B):
1. Units: \(Z+X = 8\) (no carry) or \(Z+X = 18\) (carry 1).
2. Tens: \(Y+Y + (\text{carry}) = 4\) or \(Y+Y + (\text{carry}) = 14\).
3. Hundreds: \(X+Z + (\text{carry}) = 8\).
4. From Hundreds: The carry from the tens must be 0, because if it were 1, \(X+Z=7\), which contradicts Units (8 or 18).
5. So, Carry from tens = 0. This means `X+Z = 8`.
6. This also means (from Units) that \(Z+X = 8\), so there is no carry from Units.
7. From Tens: \(Y+Y + 0 = 4\). \(2Y=4 \implies Y=2\).
8. We have \(Y=2\) and \(X+Z=8\). X and Z must be distinct and not 2.
(e.g., X=1, Z=7, Y=2. \(127 + 721 = 848\). This works).
9. The sum is \(X+Y+Z = (X+Z) + Y = 8 + 2 = 10\).
10.
In the problem `X3Y + 5YX = 133X`, X and Y represent distinct non-zero digits. What is the digit X?
Solution (C): This is from image 6.
`X3Y + 5YX = 133X`
1. Hundreds: \(X+5 + (\text{carry}) = 13\).
– If carry=0, \(X=8\).
– If carry=1, \(X=7\).
2. Units: \(Y+X = X\) (no carry) or \(Y+X = 10+X\) (carry 1).
Since Y is non-zero, \(Y=0\) is impossible. So \(Y+X = 10+X \implies Y=10\). Also impossible.
*Correction:* `Y+X` ends in `X`. This means `Y=0` or `Y=10`.
Since Y must be a non-zero digit, my assumption is wrong.
Let’s re-read the image… `+ 5YX`. The image has `+ 5YX`.
`X3Y + 5YX = 133X`
Units: `Y+X = X`? No. `Y+X` must end in `X`. This means `Y=0` or `Y=10`. `Y` must be 0.
But the image says “two different digits”. Let’s assume non-zero.
Wait, the image for Q6 says `X3Y + 5YX = 1,33X`. This implies X is the *thousands* digit.
Let’s re-read *that* image. `X3Y + 5YX = 133X`. Ah, `1,33X`.
So `X=1`. Let’s check.
`13Y + 5Y1 = 1331`.
Units: `Y+1 = 1 \implies Y=0`.
Tens: `3+Y = 3 \implies 3+0 = 3`. (Correct).
Hundreds: `1+5 = 13`. (This is 6, not 13).
The image Q6 is `X3Y + 5YX = 1,33X`.
This must be `X=1`.
`13Y + 5Y1 = 1331`.
`Y+1 = 1 \implies Y=0`.
`3+Y = 3 \implies 3+0 = 3`.
`1+5 = 13`? No, `1+5=6`. The image `1,33X` must mean `C=1, D=3, E=3, F=X`.
So the sum is `133X`. This is `1000 + 300 + 30 + X`.
` (100X + 30 + Y) + (500 + 10Y + X) = 1300 + 30 + X `
` 101X + 11Y + 530 = 1330 + X `
` 100X + 11Y = 800 `
We need an integer solution. If \(X=7\), `100(7) + 11Y = 800 \implies 700 + 11Y = 800 \implies 11Y = 100`. (No).
If \(X=8\), `100(8) + 11Y = 800 \implies 800 + 11Y = 800 \implies 11Y = 0 \implies Y=0`.
So `X=8, Y=0`.
Check: `X3Y + 5YX = 830 + 508 = 1338`.
Result `133X = 1338`.
This works! `X=8`.
10.
In the problem `X3Y + 5YX = 133X`, X and Y represent distinct digits. What is the digit X?
Solution (D):
1. Write the problem algebraically:
\((100X + 30 + Y) + (500 + 10Y + X) = 1300 + 30 + X\).
2. Combine terms:
\(101X + 11Y + 530 = 1330 + X\).
3. Subtract X and 530 from both sides:
\(100X + 11Y = 800\).
4. Since \(11Y\) must be a multiple of 100 (because \(100X\) and \(800\) are), \(Y\) must be 0.
5. \(100X + 11(0) = 800 \implies 100X = 800 \implies X = 8\).
6. The digits are \(X=8\) and \(Y=0\). They are distinct.
7. Check: \(830 + 508 = 1338\). This matches the pattern `133X`.
Score: 0 / 10
