Fredrick after spending 20% of his monthly salary in buying electronic goods and 10% of the monthly salary in repair work of furniture, invested 30% of the remaining amount in fixed deposits. If he was left with Rs. 18,963, how much is his monthly salary ?

Let monthly salary = Rs. $$100x$$

Amount spent on buying electronic goods = $$\frac{20}{100} \times 100x = 20x$$

Amount spent on repair work = $$\frac{10}{100} \times 100x = 10x$$

Amount left = $$100x - 20x - 10x = 70x$$

Amount invested in fixed deposits = $$\frac{30}{100} \times 70x = 21x$$

=> Amount left = $$70x - 21x = 49x$$

Acc to ques,

=> $$49x = 18963$$

=> $$x = \frac{18963}{49} = 387$$

$$\therefore$$ Monthly salary = 100 * 387 = Rs. 38,700