Question

A car requires 45 liters of petrol to travel a distance of 330 km.

1) the distance that the car can travel on 85 liters of petrol

2) the amount of petrol that the car owner has to pay to travel a distance of 990km if a liter of petrol costs $ 2.25.

Answer 1

1) The car travels 623.333 kilometers with 85 liters of petrol.

2) The owner of the car must buy 135 liters of petrol at a total cost of $ 303.75 to travel 990 kilometers.

Explanation:

1) The distance traveled by the car is directly proportional to the quantity of petrol. Then, we determine the distance needed by this simple rule of three:

`x = (85\,L)/(45\,L)* 330\,km`

`x = 623.333\,km`

The car travels 623.333 kilometers with 85 liters of petrol.

2) The quantity of petrol is directly proportional to the traveled distance, which is directly proportional to cost. First, we calculate the quantity of petrol spent by the car:

`x = (990\,km)/(330\,km)* 45\,L`

`x = 135\,L`

And the cost of 135 liters of petrol is:

`y = 135\,L* 2.25\,(\$)/(L)`

`y = \$\,303.75`

The owner of the car must buy 135 liters of petrol at a total cost of $ 303.75 to travel 990 kilometers.