Question

A mixture of petrol and kerosene weighing 5 kg contains 5% kerosene. How much more kerosene (approx.) must be added into it to make it 10%?

Answer 1

Answer:0.28 kg of kerosene should be added to the mixture to make it 10% kerosene solution.

Explanation:

Initial amount of the mixture = 5 kg

Amount of kerosene in 5 kg mixture =5% of 1 kg= $\frac{5\times 5}{100}=0.25 kg$

Let the mass of the kerosene added to the mixture be x

New total mass of the mixture = 5 + x kilo grams

New mass of the kerosene in (5+x )kg = 0.25 + x kg

Since 10% of kerosene in present in new mixture of (5+x) kg:

$mass\%=\frac{\text{mass of the component}\times 100}{\text{total mass of the mixture}}$

$10=\frac{(0.25+x)\times 100}{(5+x )kg}$

$x=0.277777777\approx 0.28 kg$

0.28 kg of kerosene should be added to the mixture to make it 10% kerosene solution.