Question

2. The average monthly consumption of petrol for a car for 12 months is
160 litre, if the average monthly consumption for first 8 months is 145
litre, then the average monthly consumption of petrol for the last 4
months is
(a) 190 litre
(b) 165 litre
(c) 180 litre
(d) 175 litre
(1 mark)​

Answer 1

(a) The consumption of petrol in last 4 months is 190 litre.  

Step-by-step explanation:

As given in question that consumption of petrol for a car for 12 months is 160 litre.

Consumption of petrol in first 8 months is 145 litre.

We have to find the consumption of petrol in last 4 months.

Let the consumption of petrol in last 4 months is x.

We know that,

$Average = \frac{sum\ of\ cosumption\ of\ petrol\ in\ first\ 8\ months\ +\ sum\ of\ cosumption\ of\ petrol\ in\ last\ 4\ months}{12\ months}$

$160 = \frac{145\times8\ +\ x\times4}{12}$

160 x 12 = 1160 + 4x

1920 - 1160 = 4x

760 = 4x

$\frac{760}{4} = x$

∴ x = 190 litre

Therefore, the consumption of petrol in last 4 months is 190 litre.