What number should replace the question mark in the series below? 51, 153, 76.5, 229.5, 114.75, 344.25, ?

A172.125 ✓ Correct

B1032.75

C516.375

D258.1875

Correct answer: (A) 172.125

Explanation

The next term is 172.125.

The pattern alternates: multiply by 3, then divide by 2.

51 x 3 = 153, 153 / 2 = 76.5, 76.5 x 3 = 229.5.

229.5 / 2 = 114.75, 114.75 x 3 = 344.25.

344.25 / 2 = 172.125.

Method: alternating x3 and /2 operations.

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