
A car uses 10 litres of petrol in covering a distance of 145 km.
( i ) How many kilometres will it go in 20 litres of petrol ?
( ii ) How much petrol is required to cover a distance of 261 km?
Answer
516.3k+ views
Hint: In this question what we have to do is we are provided with the quantity of petrol and what we have to find how many kilometres will a car go in 20 litres of petrol and also how much petrol is required to cover a distance of 261 km. which we can calculate by concept of : we calculate petrol needed for per kilometre then we divide total number of kilometres by total petrol needed and when we calculate petrol needed for x km then we multiply x by petrol needed for per km.
Complete step by step answer:
Now, in question the only information which is provided is that A car is covering a distance of 145 km in 10 litres of petrol. And we have to find how many kilometres a car will go in 20 litres of petrol and also how much petrol is required to cover a distance of 261 km.
Now, let us first find how many kilometres does a car cover in 1 litre of petrol.
Here, the car covers 145 kilometres of distance in 10 litres.
So, in 10 litres = 145 km distance covered.
So, distance covered by a car in 1 litre of petrol will be equals to
1 litre km
km
That is, in one litre of petrol a car travels a total distance of 14.5 km.
Now, we have to find how many kilometres a car travels in 20 litres of petrol.
So, we have 1 litre km
Then, in 20 litre of petrol, we have
km
On Simplifying, we get
Hence in 20 litres of petrol a car travels a total distance of 290 km.
Now, we have to find that, to cover 261 kilometres how much litres of petrol do cars need.
If, we have 1 litre km, then
We can re - write it as which means t cover 1 kilometre of distance, we need of petrol.
So, for 261 km of distance petrol needed will be equals to
On simplifying, we get
Dividing 2610 by 145, we get
So, to cover 261 kilometres, 18 litres of petrol is needed by a car.
Note: if it is given that in x litres of petrol, y km distance is covered by a car then km/litre gives distance covered in 1 litre of petrol and litre/km gives amount of petrol spent to cover distance of 1km. Calculation must be accurate and should be done carefully as we have to divide numbers of more than 2-digits. Always remember to place litres and km before the numerical answer to differentiate between litres and kilometres.
Complete step by step answer:
Now, in question the only information which is provided is that A car is covering a distance of 145 km in 10 litres of petrol. And we have to find how many kilometres a car will go in 20 litres of petrol and also how much petrol is required to cover a distance of 261 km.
Now, let us first find how many kilometres does a car cover in 1 litre of petrol.
Here, the car covers 145 kilometres of distance in 10 litres.
So, in 10 litres = 145 km distance covered.
So, distance covered by a car in 1 litre of petrol will be equals to
1 litre
That is, in one litre of petrol a car travels a total distance of 14.5 km.
Now, we have to find how many kilometres a car travels in 20 litres of petrol.
So, we have 1 litre
Then, in 20 litre of petrol, we have
On Simplifying, we get
Hence in 20 litres of petrol a car travels a total distance of 290 km.
Now, we have to find that, to cover 261 kilometres how much litres of petrol do cars need.
If, we have 1 litre
We can re - write it as
So, for 261 km of distance petrol needed will be equals to
On simplifying, we get
Dividing 2610 by 145, we get
So, to cover 261 kilometres, 18 litres of petrol is needed by a car.
Note: if it is given that in x litres of petrol, y km distance is covered by a car then
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