Question

A number when multiplied by 5 is increased by 80. The number is

(a) 15
(b) 20
(c) 25
(d) 30

Answer 1

$\begin{array}{l}\left(\text{b}\right)20\\ \text{Let the number be}x.\\ \\ \text{Then,}5x=x+80\\ \Rightarrow 5x-x=80\\ \Rightarrow 4x=80\\ \Rightarrow x=\frac{\sout{8}{\sout{0}}^{20}}{{\sout{4}}_1}\\ \Rightarrow x=20\\ \therefore \text{The required number is 2}0.\end{array}$