Question

A litre of kerosene oil weighs 0.819 kg and 10 litres of petrol weighs 7.02 kg, then find the ratio of the weights of kerosene oil to that of petrol per litre.
(a). 7:5
(b. )5:7
(c). 6:7
(d). 7:6

Answer 1

Hint: A ratio is a number, which expresses one quantity as a fraction of the other. In this question, work out the ratio of the weights of kerosene oil to the weights of the petrol in the same quantity that is first find the weight of the petrol per litre and then perform the ratio.

Complete step-by-step answer:
A ratio is the comparison or simplified form of two quantities of the same kind. This relation indicates how many times one quantity is equal to the other or in other words, ratio is a number, which expresses one quantity as a fraction of the other.

The quantity of the weights in the one litre kerosene oil is 0.819 Kg.
One litre kerosene oil weighs =$0.819$
Ten litre kerosene oil weighs = \[10\times 0.819=8.19\]
The quantity of the weight in the 10 litre petrol is 7.02 kg.
Ten litre of petrol weighs = 7.02
Let us consider the ratio of the 10 litres of kerosene oil to 10 litres of the petrol.
Let A and b be the 10 litres weights of kerosene oil and 10 litres weights of the petrol respectively.
Therefore, A = 8.19 and B = 7.02
The required ratio = $\dfrac{A}{B}$
The required ratio = $\dfrac{8.19}{7.02}=\dfrac{819}{702}=\dfrac{7}{6}$
Hence the correct option for the given question is option (d).
Note: Ratios can also be simplified. A common error of students is that if a ratio is not written in fraction form, then they forget to simplify it.