Question

If 10-digit number 75y97405x2 is divisible by 72, then the value of (2x-y), for the greatest value of x, is

Answer 1

Answer:

9

Step-by-step explanation:

75y97405x2 is divisible by 72

by the rules of division any number divisible by 8 when the number which made by last three digit of the number divisible by 8

it means the given number must be divided by 8 when the number 5X2 is divided by 8

so,

552 is the number which is divided by 8

X = 5

also given number is divided by 9 when sum of the digits of this is divided by 9

it means

7+5+Y+9+7+4+0+5+X+2 is divided by 9

when y = 1 , X = 5

and here 5 is also biggest value of X.

now,

2x-y = 2×5-1 = 5 - 1 = 9