Question

If the 7-digit number 134x58y is divisible by 72, then the value of (2x + y) is

• A. 7
• B. 8
• C. 9
• D. 6

Answer 1

Answer:

B. 8

7-digit number 134x58y is divisible by 72, so we can say number also divisible by 8 and 9.

Divisibility law of 8 ⇒ A number divisible by 8 if its last three-digit is divisible by 8

Divisibility law of 9 ⇒ A number is divisible by 9 if the sum of its digit is divisible by 9.

7-digit number 134x58y is divisible by 8 if its last digit will be y = 4.

7- digit number 134x584 divisible by 9 if x = 2

⇒ 1 + 3 + 4 + x + 5 + 8 + 4

⇒ 25 + x

If we put x = 2, then number become 27 which is divisible by 9.

Now, (2x + y)

⇒ (2 $\times$ 2 + 4)

⇒ 4 + 4

⇒ 8.