If 7-digit number 485A64B is divisible by 8 and 9, then find the greatest value of A + B.
Answer & explanation
Correct answer: option 3
If number is divisible by 8, last three digits are either 0 or divisible by 8
Since they are non zero, therefore the last three digits will be 640 or 648 with quotient 80 and 81 respectively.
So, B is 0 or 8
If number is divisible by 9, the sum of all the digits is divisible by 9,
Sum, if B is 0 = 4+8+5+A+6+4+0 = 27+A (So A is 0 or 9)
A+B = 0 or 9
Sum, if B is 8 = 4+8+5+A+6+4+8 = 35+A (So A is 1)
A+B = 9
Therefore highest value of A+B = 9
The correct answer is Option (3) → 9