Question

Which number is \[40\% \] less than \[90\]?
(A) \[36\]
(B) \[50\]
(C) \[60\]
(D) \[54\]

Answer 1

Hint: We can solve the question by converting the given statement in terms of algebraic equations. To find the number which is \[40\% \] less than \[90\], we will first find \[40\% \] of \[90\] for this we will use the concept of percentage and then we will subtract the result of \[40\% \] of \[90\] from \[90\]. The result of this subtraction will give us the required answer.

Complete step by step answer:
In this question, we are asked to find the number which is \[40\% \] less than \[90\].
To find the number which is \[40\% \] less than \[90\], we will first find \[40\% \] of \[90\] and then subtract the result of \[40\% \] of \[90\] from \[90\].
For this, we will first calculate \[40\% \] of \[90\] which is equal to \[\left( {\dfrac{{40}}{{100}} \times 90} \right)\].
On multiplying \[40\] and \[90\] in the numerator of the resulting fraction, we get the expression as \[\dfrac{{3600}}{{100}}\].
In the above expression, \[100\] will be cancelled out in the numerator and the denominator and we get \[36\].
Now, we need to subtract \[36\] from \[90\] to get the desired result. On doing so, we get \[\left( {90 - 36} \right)\] i.e., \[54\].
Therefore, the number is \[40\% \] less than \[90\] is \[54\]. Hence, option (D) is correct.

Note:
In this question, the concept of percentage is used. A percentage is a number or ratio expressed as a fraction of \[100\] and is often used to express a proportionate part of a total. It is often denoted using the percent sign, \['\% '\]. A percentage is a dimensionless number and has no unit of measurement.