Correct Answer - Option 4 : 10
Given:
Five-digit number 235xy is divisible by 3, 7 and 11
Concept used:
Divisibility rule of 3- The sum of its digit is divisible by 3.
Divisibility rule of 7- To make a pair of 3 from unit digit than subtract left over pair,
The result is divisible by 7.
Divisibility rule of 11- The difference of the sum of odd place and even place is zero or multiples of 11.
The result is divisible by 11.
Calculation:
235xy
For 3, x + y = 2, 5, 8, 11
For 11, (7 + y) - (3 + x) = 0 or 11
y = 2 then x = 6, x + y = 8
For 7, 562 - 023 = 539
it is also divisible by 7
number = 23562 and x = 6, y = 2
now,
3x - 4y = 18 - 8 = 10
∴ The value of 3x - 4y is 10.
