Question

For a positive integer b > 1, if the product of two numbers 6344 and 42b8 is divisible by 12, then find the least value of b.

• A. 5
• B. 7
• C. 3
• D. 4

Answer 1

Answer:

D. 4

if 12 is divisible by the product then 3 and 4 also divisible take 6344 the last two number is 44 it is divisible by 4 take 42b8 last two digits are b8 if it is divisible by 4 the b should be 2,4,6,8 checking the divisibility of 3 6344 = 6+3+4+4=17 it is not divisible by 3 so 42b8 should be divisible by 3 4+2+b+8=14+b 14+b divisible by 3 if b=2 16 it is not divisible by 3 if b=4 18 it is divisible by 3