Question

Alka spends 90% of the money that she receives every month and save ₹120.How much money does she get monthly?​

Answer 1

let the total money be x

now money she spends = 90x/100

money she saves = 120

NOW

90x/100 + 120 = x

x - 90x/100 = 120

10x/100 = 120

x = 120 x 100/10

x = 1200

she earns 1200

Answer 2

Let the money she got = x
Money she saved = 120
$money \: she \: spent = \frac{90x}{100}$
So,

$\frac{9 \cancel0x}{10 \cancel0} + 120 = x \\ \\ = > x - \frac{9x}{10} = 120 \\ \\ = > \frac{10x - 9x}{10} = 120 \\ \\ = > \frac{x}{10} = 120 \\ \\ = > x = 1200$

Therefore, money she got = 1200.