Test Index

WAEC Mathematics 2018 Paper

Question : 25

Total: 50

Find the

n^{th}

term of the sequence 2 x 3, 4 x 6, 8 x 9, 16 x 12...

Solution:

Concept:

Each term is a product of two patterns: powers of 2 and multiples of 3.

Explanation:

The sequence is

2 \times 3,\ 4 \times 6,\ 8 \times 9,\ 16 \times 12,\dots

The first factors are

2^1, 2^2, 2^3, 2^4, \dots

So the

n^{th}

first factor is

2^n

The second factors are

3, 6, 9, 12, \dots

These equal

3 \times 1,\ 3 \times 2,\ 3 \times 3,\ 3 \times 4, \dots

So the

n^{th}

second factor is

3n

Hence, the

n^{th}

term of the sequence is

2^n \times 3n

Answer:

2^n \times 3n

(Option B)

Go to Question:

Prev Question

Next Question