Question

QUESTION IN THE ATTACHMENT BELOW

Answer 1

Step-by-step explanation:

hope it helps you my friend

Answer 2

Answer:

Answer is 100

Step-by-step explanation:

s20

s20=20/2(2a+ 19d)

or 400=20/2(2a+19d)

or 400=10[12a+ 19d]

or 2a+19d=40 ....1

Also, s40=40/2(2a+19d)

or 1600=20 [2a+39d]

or 2a+39d=80 ....2

from (1) and(2)we get

a=1 and d=2

s10=10/2[2×1+(10-1)(2)]

5[2+9×2]

5[2+18]

5×20

100 is answere