Question

Find the sum of the following A.P 1) 53, 38,23,8 upto 25 term​

Answer 1

Answer:

3175

Step-by-step explanation:

Here a=53, d= - 15, n=25

Sum of first n numbers

Sn=n/2 ( 2a+(n-1)d)

Sn= 25/2(106+24(-15))

= 25/2(106-360)

= 25/2(254)

Sn = 3175