Question

If AP S20=1200 and and the last term is 80 find the first term

Answer 1

Answer:

i think you question is incomplete plz complete it

Step-by-step explanation:

Answer 2

Answer:

a=40

Step-by-step explanation:

S20=1200

Sn=n/2(a +l)=1200

where l is the last term,a is first term.

n=20

S20=20/2(a+80)=1200

10(a+80)=1200

10a+800=1200

10a=400

a=40