A salesman is allowed 5% commission on the total sale made by him plus a bonus of 1% on the excess of his sale over Rs. 20,000/-. If the total earning of Rs. 1,450/- on commission alone, find his total earnings?
A. Rs. 100
B. Rs. 90
C. Rs. 310
D. Rs. 40

Hint: We have to find his total earnings when the salesman is allowed 5% commission on the total sale made by him plus a bonus of 1% on the excess of his sale over Rs. 20,000/- If the total earning of Rs. 1,450/- on commission alone. So, first of all we have to let his total sales be $x$, then we have to take 5% of his total sales equal to its total earnings on commission alone, which is Rs. 1,450/-, from there we have to find the value of $x$.
Now, we have to find his excess sale, then we have to take 1% of his excess sale to find his total earnings.

Complete answer:
Step 1: First of all we have to let his total sales = $x$
Step 2: As given in the question, he allows 5% commission on the total sale and earns a total earnings equal to Rs. 1,450/-
Hence,
$
   \Rightarrow 5\% \times x = 1450 \\
   \Rightarrow \dfrac{5}{{100}} \times x = 1450 \\
   \Rightarrow x = 1450 \times \dfrac{{100}}{5} \\
   \Rightarrow x = 29000/ - \\
 $
Step 3: As given in the question, He gives a bonus of 1% on the excess of his sale over Rs. 20,000/-
So, first of all we have to find his excess sale that is mentioned below:
Excess sale $ = 29000 - 20000$
$ \Rightarrow 9000/ - $
So, his total earnings be,
$
   \Rightarrow 1\% \times 9000 \\
   \Rightarrow \dfrac{1}{{100}} \times 9000 \\
   \Rightarrow 90/ - \\
 $

His total earnings be 90/- hence, option (B) is correct.

Note:
It is necessary that we have to determine the 5% of the amount we let for the total sale to determine the 5% of the commission form the total sale.