Question

Find out the values of following mathematical expressions :
20% of 400 kg
36% of 825 km
$33\dfrac{1}{3}$% of 66 boxes
100% of 28.80

Answer 1

Hint: Here we will perform basic operations of multiplication, division and also use the formula of percentage to solve the question.

Complete step-by-step answer:
Now, multiplication is used to multiply two or more numbers, digits etc. It is denoted by x and in the commonly used language ‘of’ is written for multiplication. Also, the concept of percentage is used. Percentage is denoted by the sign %. Percentage is a number or ratio expressed as a fraction of 100. In other words, percentage means division by 100. Example is 45% which is equal to $\dfrac{{45}}{{100}}$ or 0.45.

Now, according to the question 20% of 400 kg can be written as,
$ \Rightarrow $20% of 400 kg = \[\dfrac{{20}}{{100}}\] x 400 kg = 80 kg

36% of 825 km can be written as,
$ \Rightarrow $36% of 825 km = $\dfrac{{36}}{{100}}$ x 825 km = 297 km

$33\dfrac{1}{3}$ is to be converted in simple form. So, $33\dfrac{1}{3}$ can be written as $\dfrac{{100}}{3}$. So, $33\dfrac{1}{3}$% of 66 boxes can be written as,
$ \Rightarrow $$33\dfrac{1}{3}$% x 66 boxes = $\dfrac{{100}}{3}$% x 66 boxes = $\dfrac{{100}}{3}\left( {\dfrac{1}{{100}}} \right)$ x 66 boxes = 22 boxes

100% of 28.80 can be written as, 1 of 28.80 because \[\dfrac{{100}}{{100}}\] = 1, so 100% of 28.80 can be written as,
$ \Rightarrow $100% of 28.80 = $\dfrac{{100}}{{100}}$ x 28.80 = 28.80

So, 20% of 400 kg = 80 kg
36% of 825 km = 297 km
$33\dfrac{1}{3}$% of 66 boxes = 22 boxes
100% of 28.80 = 28.80

Note: In such types of easy questions, it is important that no calculation error should be done. You have to take care that the calculation is done properly. Calculation errors are the main error in such types of problems. Also, keep in mind that the formula of percentage is also very important.