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### Question 1

If 7% of A + B = 11% of A - B, then what percent of B is A?

**A**

$4{1/2}$ %.

**B**

$5{1/2}$ %.

**C**

$3{1/2}$ %.

**D**

$3{3/4}$ %.

**Soln.**

**Ans: a**

We have been given 7% of A + B = 11% of A - B, so ${A + B}/{A - B}$ = $11/7$. By componendo and dividendo, ${(A + B) + (A - B)}/{(A + B) - (A - B)}$ = ${11 + 7}/{11 - 7}$, which gives $A/B$ = $18/4$ = ${9/2}$, which is same as: $4{1/2}$%

### Question 2

In a sample there are 1440 items having a value of 50°C. 20% values are below 50°C, and the number of values above 50°C is $2/3$ of the items having a value of 50°C. What is the size of the sample?

### Question 3

A number is first increased by 60%, and thereafter it is reduced by 60% again. What is the overall reduction?

**A**

36 %.

**B**

38 %.

**C**

34 %.

**D**

40 %.

**Soln.**

**Ans: a**

Let us derive the shortcut formula first, so that you can remember it and use it when the need arises. Suppose the number is 100, and let the increase be x%. The number becomes 100 + x. When it is reduced by x%, we get 100 + x - $((100 + x) × x)/100$ = 100 + x - $(x + x^2/100)$ = 100 - $x^2/100$, hence a reduction of $x^2/100$ = 36%

### Question 4

The number of online customers increased from 625 to 2075. What is the percentage increase?

### Question 5

If 4% of A + B = 9% of A - B, then what percent of B is A?

**A**

$2{3/5}$ %.

**B**

$4{1/2}$ %.

**C**

$1{1/7}$ %.

**D**

4 %.

**Soln.**

**Ans: a**

We have been given 4% of A + B = 9% of A - B, so ${A + B}/{A - B}$ = $9/4$. By componendo and dividendo, ${(A + B) + (A - B)}/{(A + B) - (A - B)}$ = ${9 + 4}/{9 - 4}$, which gives $A/B$ = $13/5$ = ${13/5}$, which is same as: $2{3/5}$%

This Blog Post/Article "Percentages Quiz Set 001" by Parveen (Hoven) is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Updated on 2017-04-07.