Question

Find the percentage change, when a number is changed from.: (i) 80 to 100 (ii) 100 to 80 (iii) 6.25 to 7.50

Answer 1

(i) Original number = 80
New Number = 100,
Change = (100-80)= 20
$\therefore$ Percentage change (increase)
= $\frac{20}{80}\times 100$ = 25%
(ii) Original number = 100
New Number = 80,
Change = (100-80)= 20
$\therefore$ Percentage change (decrease) = $\frac{20}{100}\times 100$
= 20%
(iii) Original number = 6.25,
New Number = 7.50,
Change = (Increase)= (7.50-6.25)= 1.25
$\therefore$ increase = $\frac{1.25}{6.25}\times$ 100 = 20%