What is the value of M and N respectively? If M39048458N is divisible by 8 &…
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What is the value of M and N respectively? If M39048458N is divisible by 8 & 11; where M & N are single digit integers?
- A.
9, 2
- B.
6, 4
- C.
5, 4
- D.
7, 2
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Show answer & explanation
Correct answer: B
Step 1 — Use divisibility by 8:
The last three digits of the number are 58N, so the number 580–589 must contain a multiple of 8.
Among 580–589, only 584 is divisible by 8 (8 × 73 = 584). Therefore N = 4.
Step 2 — Use divisibility by 11:
Write the digits in positions 1 to 10: M, 3, 9, 0, 4, 8, 4, 5, 8, 4 (we substitute N = 4).
Sum of digits in odd positions = M + 9 + 4 + 4 + 8 = M + 25.
Sum of digits in even positions = 3 + 0 + 8 + 5 + 4 = 20.
Difference = (M + 25) − 20 = M + 5. For the number to be divisible by 11, this difference must be 0 or a multiple of 11.
Since M is a single digit, the only possibility is M + 5 = 11, so M = 6.
Answer: M = 6, N = 4