Question

Karan buys petrol at Rs.8, Rs.7.50 and Rs.8.50 per litre for three successive years. What is the approximate average cost per litre of petrol if he spends Rs.4000 on petrol each year?

• A. 7.68
• B. 7.98
• C. 8.28
• D. 8.84
• E. 7.88

Answer 1

The correct option is B

7.98

Total amount spent = Rs.(3 x 4000) = Rs.12000.

Average cost = $\frac{12000}{\left(\frac{4000}{8}\right)+\left(\frac{4000}{7.5}\right)+\left(\frac{4000}{8.5}\right)}$ = $\frac{6120}{767}$ = Rs.7.98