Question

A desel tank can hold 4000 litres of water when filled to the brim. It is 7/8 filled. If 2/5 of the water is removed, how much more desel must be added in order to fill the tank ?​

Answer 1

Given :

Total quantity of a diesel tank : 4000 litres

Part of the tank filled : ⅞

Part of the water removed : ⅖

To find :

More diesel to be added to fill the tank.

Solution :

First, we should find the amount of tank filled.

Amount of tank filled :

$\sf \dashrightarrow \dfrac{7}{8} \: of \: 4000$

$\sf \dashrightarrow \dfrac{7}{8} \times 4000$

$\sf \dashrightarrow \dfrac{7 \times 4000}{8} = \dfrac{28000}{8}$

$\sf \dashrightarrow \cancel \dfrac{28000}{8} = 3500$

Now, we should find the amount of water rover.

Amount of water removed :

$\sf \dashrightarrow \dfrac{2}{5} \: of \: 3500$

$\sf \dashrightarrow \dfrac{2}{5} \times 3500$

$\sf \dashrightarrow \dfrac{2 \times 3500}{5} = \dfrac{7000}{5}$

$\sf \dashrightarrow \cancel \dfrac{7000}{5} = 1400$

Part of water remaining :

$\sf \dashrightarrow 3500 - 1400$

$\sf \dashrightarrow 2100 \: litres$

Now, we can find that how much more diesel is required to fill the tank completely.

More diesel required :

$\sf \dashrightarrow 4000 - 2100$

$\sf \dashrightarrow 1900 \: litres$

Hence, 1900 litres more amount of diesel is required to fill the tank up to the brim.