Question

In Ap if the 12th term is -13 and the sum of its first four term is 24, find the sum of its first 10terms

Answer 1

Answer:

180

Step-by-step explanation:

a12=a+11d=-13        eq(1)

s4=4/2*(2a+3d)=24

4a+6d=24              eq(2)

4eq(1)-eq(2)=38d=-76

d=-2

a=-13+22=9

s10=10/2*(18-(-18))=5*36=180