Question

If the sum of first 15 terms of an A.P. is 675 and its first term is 10. then find 25th term.​

Answer 1

Answer:

253.5 is the correct answer.

l hope this answer helps you.

Answer 2

Step-by-step explanation:

S15=675

n=15

a=first term=10

d=?

we know that

Sn = n/2 [2a+(n-1)×d]

S15=15/2 [2×10+(15-1)×d]

675=15/2 [20+14d]

1350=15×20+14d

1350=300+14d

1350-300=14d

14d=1050

d=75

to find 25th term

b=25

d=75

a=10

we know that

tn =a+(n-1)d

t25=10+(25-1)×75

t25=10+24×75

t25=1738

I think it will help you