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.
The least number to be added to the numbers to make them divisible by 9 is equal to the difference of the least multiple of 9 greater than the sum of the digits and sum of the digits.Sum of digits = 15.Nearest multiple of 9 greater than sum of digits = 18.Hence 3 has to be added.
EXAMIANS