Question

Which of the following rational number is in the standard form?

(a) $\frac{16}{21}$

(b) $\frac{16}{24}$

(c) $\frac{21}{15}$

(d) $\frac{-21}{56}$

The question was asked in a national level competition.

This is a very interesting question from Properties of Rational Numbers in chapter Rational Numbers of Mathematics – Class 8

Answer 1

Correct choice is (a) $\frac{16}{21}$

The best I can explain: A rational number is said to be in it’s standard form when the numbers cannot be further reduced.

Here, we can see that the options other than the option $\frac{16}{21}$ can be reduced.

When $\frac{16}{24}$ is reduced, we get $\frac{2}{3}$… Standard Form.

When $\frac{21}{15}$ is reduced, we get $\frac{7}{5}$… Standard Form.

When $\frac{-21}{56}$ is reduced, we get $\frac{-3}{8}$… Standard Form.