Test Index

JAMB Mathematics 2017 Paper

© africaexams.com

Question : 26

Total: 44

Evaluate

\frac{0.00000231}{0.007}

and leave the answer in standard form

3.3 x 10^-4
3.3 x 10^-3
3.3 x 10^-5
3.3 x 10^-8

Solution:

Concept:

Standard form expresses a number as

A \times 10^n

, where

1 \le A < 10

.

Explanation:

Rewrite each decimal using powers of

10

:

0.00000231 = 2.31 \times 10^{-6}

0.007 = 7 \times 10^{-3}

Now divide:

\frac{0.00000231}{0.007} = \frac{2.31 \times 10^{-6}}{7 \times 10^{-3}}

= \frac{2.31}{7} \times 10^{-6 - (-3)}

= 0.33 \times 10^{-3}

Write

0.33

in standard form:

0.33 \times 10^{-3} = 3.3 \times 10^{-4}

Answer:

3.3 \times 10^{-4}

(Option A).

© africaexams.com

Go to Question:

Prev Question

Next Question