Question

In an AP of natural numbers S20 +S15=..........................?

Answer 1

Answer:

A.P:1,2,34........20

a=1,d=2-1=1,n=20

S20=n/2(2a+(n-1)d)

=20/2(2(1)+(20-1)(1)

=10(2+19)

=10(21)

=210

a=1,d=2-1=1,n=15

S15=n/2(2a+(n-1)d)

=15/2(2(1)+(15-1)(1)

=15/2(2+14)

=15/2(16)

=15(8)

=120

S20+S15=210+120

=330

Step-by-step explanation:

I hope this answer may help you