Question

# If the 7th and 13th terms of an AP are 34 and 64 respectively, then its 18th term would be ___

A
87
B
88
C
89
D
90

Solution

## The correct option is D 89an=a+(n−1)da+6d=34−−−(1)a+12d=64−−−(2)Solving (1) and (2),a=4 and d=5a18=4+(17)5=89

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