Question

If a1,a2,a3..... are in AP, such that a1+a7+a16=40, then find the sum of the first 15 terms of the AP​

Answer 1

Answer:

200

Step-by-step explanation:

a1+a7+a16=(a)+(a+6d)+(a+15d)=40

3a+21d=40

a+7d=(40/3)

Sum of first 15 terms

=15*(2a+14d)/2

=15*(a+7d)

=15*(40/3)

=200