Question

A drum of petrol is 3/4 full. When 30 L of oil is drawn out from it, it is 7/12 L full. Find the capacity of the drum. ​

Answer 1

Given :-

▪ A drum of petrol is 3/4 full. When 30 L of oil is drawn out from it, it becomes 7/12 full.

To Find :-

▪ Capacity of the drum.

Solution :-

Let the capacity of the drum be x L, so before drawing out 30 L of oil, the drum had 3x / 4 L of petrol.

And, After drawing out 30 L of oil, the drum is then 7x / 12 L full of petrol.

This situation can be expressed in an algebraic expression as,

⇒ { 3x / 4 } - 30 = 7x / 12

⇒ (3x - 120) / 4 = 7x / 12

⇒ 3x - 120 = 7x / 3

⇒ 9x - 360 = 7x

⇒ 9x - 7x = 360

⇒ 2x = 360

⇒ x = 180 L

Since, we assumed the capacity of the drum as x L.

Hence, The capacity of the drum is 180 L.

Answer 2

Question

A drum of petrol is 3/4 full. When 30 L of oil is drawn out from it, it is 7/12 L full. Find the capacity of the drum.

Given

• A drum of petrol is 3/4 full

30L of oil is drawing out from it then it is 7/2 l

Find

• Capacity of drum or volume ?

Solution

Let,

• The capacity of drum be " x " litre

Drum was $\sf \dfrac{3x}{4}$ part filled.

• 30 litres oil drawn then

• it become, $\sf\dfrac{7x}{12}$ part.

Now,

According To Question

$\sf ⇒\dfrac{3X}{4} - \dfrac{7X}{12} = 30$

$\sf ⇒\dfrac{(9X - 7X)}{12 }= 30$

$\sf ⇒2X = 360$

$\sf ⇒x= \dfrac{\cancel{360}}{\cancel{2}}$

$\sf ⇒X = 180 \:litre$

Hence

• The capacity of drum is 180L