Question

12. (i) What number when increased by 15% becomes 299?
(ii) On decreasing a number by 18%, it becomes 697. Find​

Answer 1

1st Answer

Let the number be y.

According to the question,

$\sf \dashrightarrow y + 15\% \: of \: y = 299$

$\sf \dashrightarrow y + \dfrac{15}{100} \times y = 299$

$\sf \dashrightarrow y + \dfrac{15y}{100} = 299$

$\sf \dashrightarrow y + \dfrac{3y}{20} = 299$

$\sf \dashrightarrow \dfrac{20y + 3y}{20} = 299$

$\sf \dashrightarrow \dfrac{23y}{20} = 299$

$\sf \dashrightarrow 23y = 299 \times 20$

$\sf \dashrightarrow 23y = 5980$

$\sf \dashrightarrow y = \dfrac{5980}{23}$

$\sf \dashrightarrow y = 260$

2nd Answer

$\sf \dashrightarrow m - 18\% \: of \: m = 697$

$\sf \dashrightarrow m - \dfrac{18}{100} \times m = 697$

$\sf \dashrightarrow m - \dfrac{18m}{100} = 697$

$\sf \dashrightarrow m - \dfrac{9m}{50} = 697$

$\sf \dashrightarrow \dfrac{50m - 9m}{50} = 697$

$\sf \dashrightarrow \dfrac{41m}{50} = 697$

$\sf \dashrightarrow 41m = 697 \times 50$

$\sf \dashrightarrow 41m = 34850$

$\sf \dashrightarrow m = \dfrac{34850}{41}$

$\sf \dashrightarrow m = 850$