Question

Q8= A car travels 420 km in 15 litres of petrol.
(i) How much distance will it cover in 8 litres?
(ii) How much litres of petrol is required to travel 70 km.​

Answer 1

Answer:

i) distance car travels in 1 litre of petrol=420÷15

=28 km

distance travels in 8 litres= 8×28

=224km

Answer 2

Given

In 420 km the car can travel with 15 lites of petrol.

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To Find

(i) How much distance will it cover in 8 litres?

(ii) How much litres of petrol is required to travel 70 km.

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Concept used.

๑Here the concept of Unitary method is used. In this method we first find the value of single unit by multiplying the necessary value by single unit.

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Solution

(i) We know that

$\sf{ \to \: Distance \: covered \: in \: 15 \: litres \: of \: petrol =420 \: km.} \\ \\ \sf{ \to Distance \: covered \: in \: 1 \: litres \: of \: petrol =\frac{420}{15} km} \\ \\ \sf{ \to Distance \: covered \: in \: 1 \: litres \: of \: petrol = 28 \: km.} \\ \\ \sf{ \to Distance \: covered \: in \: 8 \: lites \: of \: petrol= 28×8= \color{red} 224 \: km.}$

Therefore the distance covered in 8 lites of petrol is 224 km.

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$\sf{ (ii) \: Petrol \: needed \: to \: cover \: 420 \: km= 15 L} \\ \\ \sf{ \to petrol \: needed \: to \: cover \: 1 km = \frac{15}{420} Litre} \\ \\ \sf{ \to Petrol \: needed \: to \: cover \: 70 \: km = \frac{15×70}{420}} \\ \\ \sf{ \to Petrol \: needed \: to \: cover \: 70 \: km = \color{green} 2.5 litres}$

Therefore 2 5 litres of petrol is required to cover 70km of distance.

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