Question

Tick (✓) the correct answer:
Four-fifths of a number is greater than three-fourths of the number by 4. The number is
(a) 12
(b) 64
(c) 80
(d) 102

Answer 1

(c) 80

$$\begin{gathered} \mathrm{Let}\mathrm{the}\mathrm{number}\mathrm{be}\mathrm{x}. \\ \therefore \frac{4}{5}x=\frac{3}{4}x+4 \\ \Rightarrow \frac{4x}{5}=\frac{3x+16}{4} \\ \Rightarrow 16x=15x+80 \\ \Rightarrow 16x-15x=80 \\ \Rightarrow x=80 \end{gathered}$$