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JAMB Mathematics 2015 Paper

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Question : 37

Total: 61

Determine the third term of a geometrical progression whose first and second term are 2 and 54 respectively

1458
1485
1345
1258

Solution:

Concept:

In a geometric progression, each term is found by multiplying the previous term by a constant ratio

r

.

Explanation:

First term:

a = 2

Second term:

ar = 54

Substitute

a = 2

:

2r = 54

r = \frac{54}{2} = 27

Third term:

ar^2 = 2 \times 27^2

= 2 \times 729

= 1458

Answer:

The third term is

1458

, which is option A.

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