Question

A certain quantity of petrol is found to be adulterated to the extent of 10%. What proportion of the adulterated petrol should be replaced with pure petrol to take the purity level to 98%?

Answer 1

The quantity of petrol is found to be adulterated to the extent of 10%.

Now we need to figure out what proportion of the adulterated petrol should be replaced with pure petrol to take the purity level to 98%.

Since 10% is adulterated that implies 90% of the petrol is pure hence, we can form an equation that will help to answer the proportion to take the purity level to 98%.

$x+\frac{9}{10} (100-x)=98$

Where 'x' is the percentage of proportion needed to be replaced.

Solve for 'x':

$x+\frac{9}{10} (100-x)=98$

$x+90-\frac{9x}{10} = 98$

$\frac{10x-9x}{10}=8$

x = 80

Therefore, 80% of the adulterated petrol should be replaced with pure petrol to take the purity level to 98%.