Question

If the ratio of two numbers is 7 : 2 and the bigger of the two numbers is 21, what is the smaller number?

Answer 1

Ratio of two numbers = 7:2$=\frac{7}{2}$
The bigger number = 21
Let the smaller number be x.
Because the given ratio of two numbers is greater than 1, the ratio should be of the bigger number to the smaller number.
∴ Ratio of the bigger number to the smaller number = 21:x$=\frac{21}{x}$

Because the two ratios are the same, $\frac{7}{2}=\frac{21}{x}$.
Also, because the numerator of the second ratio is three times the numerator of the first ratio, x = 2 × 3 = 6.
Thus, the smaller number is 6.