Question

find the greatest number
which divides 615 and 963 leaving the remainder 6 in each case

Answer 1

615 - 6 = 609
963 - 6 = 957 

609=3×3×29
957=3×11×29
HCF=3×29=87 
The largest number that divides 615 and 963 leaving remainder 6 in both numbers  is 87.