Let the ten's digit be x and unit's digit be y. Then, number 10x + y.Number obtained by interchanging the digits = 10y + x.(10x + y) + (10y + x) = 11(x + y)which is divisible by 11.
LCM of 10, 15, 25 = 150When we drive 2641 by 150 the remainder is 91.But the remainder should be 7.So, the number to be subtracted from 2641 is 91 - 7 = 84.
EXAMIANS