Question

Rohit is $\dfrac{7}{{10}}$ meters tall. His sister is twice as tall as him. His father is $\dfrac{2}{5}$ meters taller than his sister. How tall is Rohit’s father?

Answer 1

Hint: In this type of questions, appropriate mathematical equations needed to be formed which should satisfy the given conditions of the question. In this question, only the height of Rohit has been given and the height of his sister depends on the height of Rohit and the height of his father depends on the height of his sister which consequently depends on the height of Rohit. So, first of all calculate the height of Rohit’s sister, which is two times of Rohit’s height and then his father’s height which is $\dfrac{2}{5}$ meters more than his sister’s height.

Complete step by step answer:
Given, the height of Rohit is $\dfrac{7}{{10}}$ meters.
$Rohit’s\;height = \dfrac{7}{{10}} - - - - (i)$

According to the question, Rohits sister is twice the height of Rohit. So, multiplying equation (i) with 2 we get, the height of Rohit’s sister as:
$
Sister’s\;height = 2 \times \dfrac{7}{{10}} \\

= \dfrac{7}{5}{\text{ meters}} - - - - (ii) \\
 $
Now, it has been given that the height of Rohit's father is $\dfrac{2}{5}$ meters more than his sister’s height. So, add $\dfrac{2}{5}$ to equation (ii) to get the height of Rohit’s father.
So, the height of Rohit’s father is given as:
$
Father’s\;height = \dfrac{7}{5} + \dfrac{2}{5} \\
= \dfrac{{7 + 2}}{{5}} \\
= \dfrac{{9}}{{5}}{\text{ meters}} - - - - (iv) \\
 $
Hence, the height of Rohit’s father is $\dfrac{{9}}{{5}}{\text{ meters}}$.

Note: Students should be aware about the mathematical terms like than, by, more than, less than, etc. so that appropriate mathematical equations can be formed satisfying the conditions given in the question.