CAT Exam

Sum of first 25 terms of an AP is 525; sum of the next 25 terms is 725; what is the common difference?

Read Solution (Total 2)

sum of first 25 terms of an A.P is 525
we know that s(25)=n/2(2a+(n-1)d)=25/2(2a+24d)=525-(1)
sum of next 25 terms of an A.P is 725,so that total number of terms is 50
so that it can be written as 50/2(2a+49d)=(725+525)-(2)
1 can be written as 2a+24d=42-(3)
2 can be written as 2a+49d=5o-(4)
so that 3&4 is solved,we get 25d=8=>d=8/25
common difference is 8/25.
11 years agoHelpfull: Yes(7) No(0)

ans =-17/25
11 years agoHelpfull: Yes(0) No(4)

CAT Other Question

The sum of the first 20 terms of the series -12 + 22 - 32 + 42 - 52 + 62 ... is: Sum of first 12 terms of a GP is equal to the sum of the first 14 terms in the same GP. Sum of the first 17 terms is 92, what is the third term in the GP?