Question

If $ 5 $ litres of a solution are $ 20\% $ acidic, how much of the solution is acid?

Answer 1

Hint: In this question it is given that in $ 5 $ litres of a solution are $ 20\% $ acidic. We need to determine the amount of solution that is acid. We will consider the amount of acid in the solution to be $ x $ . Then, we will determine the value $ 20\% $ of $ 5 $ litres, which is the required value.

Complete step by step solution:
Let us consider the amount of acid in the solution to be $ x $ .
We know that $ 20\% = \dfrac{{20}}{{100}} $
Thus, $ 20\% $ of $ 5 $ litres is,
 $ x = \dfrac{{20}}{{100}} \times 5 $
 $ x = \dfrac{1}{5} \times 5 $
Therefore, $ x = 1 $ litre
Hence, $ 1 $ litre of the solution is acidic.
So, the correct answer is “$ 1 $ litre”.

Note: It is worth noting here that in mathematics, a percentage is a number or ratio expressed as a fraction of $ 100 $ . It is often denoted using the percentage sign $ \% $ . A percentage is a dimensionless number and it has no unit of measurement. It is very popular since it can describe situations that involve large numbers as well as very small numbers. A percentage is also a way to express the relationship between two numbers as a fraction of $ 100 $ . In other words, the percentage tells us how one number relates another.