Question

A car owner buys petrol at Rs. $7.50$, Rs. $8.00$ and Rs. $8.50$ per litter for $3$ successive years. If he spends Rs. $4000$ each year , then the average cost per litter of petrol is

• A. Rs. $8$
• B. Rs.$8.25$
• C. Rs. $7.98$
• D. none of these

Answer 1

The correct option is C Rs. $7.98$

Given,

Qty of petrol used first year$=\frac{4000}{7.5}=533.333Ltrs.$

Petrol used second year$=\frac{4000}{8}=500Ltrs.$

And in 3rd year$=\frac{4000}{8.5}=470.588Ltrs.$

Hence total Qty of petrol consumed in 3 years$=533.333+500+470.588=1503.92Ltrs.$

And money spent in 3years $=4000\times 3=12000RS.$

Hence average cost of per Ltr petrol$=\frac{12000}{1503.92}=7.98$

Answer is $7.98$ RS per Ltrs.