Question

The A.P. in which 4th term is -15 and 9th term is -30. Find the sum of the first 10 numbers. Solve the word problem

Answer 1

Answer:

-195

Step-by-step explanation:

a4=-15

a+3d=-15. (1)

a9=-30

a+8d=-30. (2)

subtract (1) and (2)

-5d=15

d=-3

put this value in 1

then a=-6

sum of 10 terms=n/2(2a+(n-1)d)

=10/2(-12+(10-1)(-3))

=5(-12-27)

=5(-39)

=-195