Question 13 Marks
Find a number whose one-third part exceeds its one-fifth part by 20.
Answer
View full question & answer→Let the number $=x$
According to the condition
$ \begin{aligned} & \frac{1}{3} \mathrm{x}-\frac{1}{5} \mathrm{x}=20 \\ & \Rightarrow \frac{5 \mathrm{x}-3 \mathrm{x}}{15}=20 \ldots(\text { LCM of } 3, \text { and } 5=15) \\ & \Rightarrow \frac{2 \mathrm{x}}{15}=20 \\ & \Rightarrow \mathrm{x}=\frac{20 \times 15}{2} \\ & \Rightarrow \mathrm{x}=150 \end{aligned} $
$\therefore$ Number $=150$
According to the condition
$ \begin{aligned} & \frac{1}{3} \mathrm{x}-\frac{1}{5} \mathrm{x}=20 \\ & \Rightarrow \frac{5 \mathrm{x}-3 \mathrm{x}}{15}=20 \ldots(\text { LCM of } 3, \text { and } 5=15) \\ & \Rightarrow \frac{2 \mathrm{x}}{15}=20 \\ & \Rightarrow \mathrm{x}=\frac{20 \times 15}{2} \\ & \Rightarrow \mathrm{x}=150 \end{aligned} $
$\therefore$ Number $=150$