Rajan spent 10% of his salary on rent. He spent 20% of the remaining part of the salary on transport. After which he spent 40% of the balance of the salary on food. Further, he spent 80% of the balance on various bills. He deposits ₹5000 in the bank and kept the remaining ₹1480 for his own petty expenditure. Find his monthly salary (in ₹).

75000

Let total salary be Rs. 100x

Salary spent on rent = $\frac{1}{10}$ × 100x = 10x

Remaining salary = 100x - 10x = 90x

Remaining salary spent on transport = 20% of 90x

=$\frac{1}{5}$ × 90x   = 18x

Remaining salary spent on food = 40% of 72x

= $\frac{2}{5}$ × 72x = 28.8x

Remaining salary spent on various bills = 80% of 43.2x

= $\frac{4}{5}$ × 43.2x = 34.56x

Remaining salary = 100x – (10 + 18 + 28.8 + 34.56)x

= (100 – 91.36)x

= 8.64x

Money in bank and saved for his own expenditure = Rs. (5000 + 1480)

= 6480
According to question ,

 8.64x = Rs. 6480

x = $\frac{6480}{8.64}$

x = 750

100x = 750 × 100

 So , Total salary Rs. 75,000