Find the third common term between the two Arithmetic Progression series 3, 7, 11, 15, ... and 1, 6, 11, 16, ...

A31

B43

C51 ✓ Correct

D47

Correct answer: (C) 51

Explanation

The third common term is 51.

First AP: terms leave remainder 3 on division by 4.

Second AP: terms leave remainder 1 on division by 5.

First common term = 11, common difference = LCM(4,5) = 20.

Common terms 11, 31, 51; third = 51.

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