Question Detail

If 15% of 40 is greater than 25% of a number by 2, the number is

Answer: Option B

Explanation:

15/100 * 40 - 25/100 * x = 2 or x/4 = 4 so x = 16

1. A student multiplied a number by 3/5 instead of 5/3. What is the percentage error.

Answer: Option A

Explanation:

Let the number be x,
then,
\begin{aligned}
\frac{5}{3} - \frac{3}{5} = \frac{16}{15}x
\end{aligned}

Error% = \begin{aligned}
(\frac{16}{15}x * \frac{3}{5} * 100)% = 64%
\end{aligned}

2. What will be the fraction of 4%

1/20
1/50
1/75
1/25

Answer: Option D

Explanation:

4*1/100 = 1/25.

Friends I know it is quite simple, but trust me while solving percentage questions in Hurry we use to do these types of mistake only. So I recommend you to have a bit practise of this.

3. Rahul's Mathematics test had 75 problems, 10 arithmetic, 30 algebra, 35 geometry problems. Although he answered 70% of arithmetic, 40% of arithmetic and 60% of geometry problems correctly, still he got less than 60% problems right. How many more questions he would have to answer more to get passed

Answer: Option A

Explanation:

Number of questions attempted correctly = (70% of 10 + 40% of 30 + 60% of 35)
= 7 + 12 + 21 = 40.

Questions to be answered correctly for 60% = 60% of total quations
= 60 % of 75 = 45.

He would have to answer 45 - 40 = 5

4. 2.09 can be expressed in terms of percentage as

2.09%
20.9%
209%
0.209%

Answer: Option C

Explanation:

While calculation in terms of percentage we need to multiply by 100, so
2.09 * 100 = 209.

5. Two numbers are less than third number by 30% and 37% respectively. How much percent is the second number less than by the first

Answer: Option C

Explanation:

Let the third number is x.
then first number = (100-30)% of x
= 70% of x = 7x/10

Second number is (63x/100)

Difference = 7x/10 - 63x/100 = 7x/10

So required percentage is, difference is what percent of first number

=> (7x/100 * 10/7x * 100 )% = 10%