If in an AP. , S5-35 and S4th22 find the 5 term. – InterviewSolution

1.

If in an AP. , S5-35 and S4th22 find the 5 term.

Answer»

S5=35

n=5

Formula

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

35=5/2(2a+4d)

70=5(2a+4d)

5(14)=5(2a+4d)

14=2a+4d…………1

S4=22

n=4

22=4/2(2a+3d)

11=2a+3d……..2

1–2

d=3

Substitute d value in 2

11=2a+3(3)

11=2a+9

2a=11–9

2a=2

a=1

Formula

Si=n/2(a+ai)

S5=n/2(a+a5)

35=5/2(1+a5)

14=1+a5

a5=13

5th term 13

Discussion

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