Question

The salary of a man has increased by 20%. If he now gets Rs.3,000, his salary before the increase was
(a) Rs.2,000
(b) Rs.2,300
(c) Rs.2,400
(d) Rs.2,500

Answer 1

Hint: In this question, we first need to assume some variable x as his salary before increasing. Now, we need to add 20% of that assumed value x which can be found by using the percentage formula given by \[\dfrac{x}{100}\times y\] to x and then equate it to Rs.3,000. Then on further simplifying the equation formed we get the value of x.

Complete step-by-step answer:
Now, from the given question the increase in salary is 20%.
Now, let us assume the salary of the man before increasing as Rs. x.
Let us now find the amount of increment from the percentage given.
As we already know from the percentage formula that x% of y is given by
\[\Rightarrow \dfrac{x}{100}\times y\]
Now, on comparing with the above formula we have
\[x=20,y=Rs.x\]
Now, the 20% increase in the salary on substituting the respective values is given by
\[\Rightarrow x+\dfrac{20}{100}\times x\]
Now, this can be further written as
\[\Rightarrow \dfrac{120x}{100}\]
Now, given in the question that the salary after increment is Rs.3,000
Let us now equate this with the value we found in terms of x
\[\Rightarrow \dfrac{120x}{100}=3000\]
Now, on further simplification we get,
\[\Rightarrow \dfrac{6x}{5}=3000\]
Now, on cancelling out the common terms on both sides we get,
\[\Rightarrow \dfrac{x}{5}=500\]
Let us now multiply with 5 on both sides
\[\Rightarrow x=500\times 5\]
Now, on further simplification we get,
\[\therefore x=Rs.2,500\]
Hence, the correct option is (d).

Note:Instead of considering an increase in 20% of his salary before to his salary we can also solve it by considering decrease in 20% of his salary from Rs.3,000 given his salary before. Then simplify the equation accordingly to get the value of x. Both the methods give the same result.It is important to note that we need to add 20% of x to x because the salary is being increased because considering the minus sign here changes the complete result. It is also to be noted that while rearranging or simplification we should not neglect any terms or do incorrect calculation.