Let Alka’s monthly income be ₹ x.
Alka spends 90% of the money that she receives every month.
∴ Amount spent by Alka = 90% of x
= \(\frac{90}{100}\) × x = 0.9x 100
Now, Savings = Income – Expenditure
∴ 120 = x – 0.9x
∴120 = 0.1 x
∴ \(x = \frac{120}{0.1} = \)\(\frac{120\times10}{0.1\times10}\)
∴ x = 1200
Alka gets ₹ 1200 monthly.