Question

1.   In an AP, if the a3=10 and a5=16 then fourth term and common difference is: ________

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Answer 1

Answer:

$15$

Given: d=3

We know:

an=a+(n−1)d

∴a20−a15=[a+19d]−[a+14d]

                     =5d

                     =5×3

                     =15

Hence, the answer is 15.