Question Detail

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}

1. A batsman scored 120 runs which included 3 boundaries and 8 sixes. What percent of his total score did he make by running between the wickets.

Answer: Option B

Explanation:

Number of runs made by running = 110 - (3 x 4 + 8 x 6)
= 120 - (60)
= 60

Now, we need to calculate 60 is what percent of 120.

=> 60/120 * 100 = 50 %

2. 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

3. 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.

4. In a hotel, 60% had vegetarian lunch while 30% had non-vegetarian lunch and 15% had both type of lunch. If 96 people were present, how many did not eat either type of lunch ?

Answer: Option D

Explanation:

\begin{aligned}
n(A) = \left(\frac{60}{100}*96\right) = \frac{288}{5} \\
n(B) = \left(\frac{30}{100}*96\right) = \frac{144}{5} \\
n(A\cap B) = \left(\frac{15}{100}*96\right) = \frac{72}{5} \\
\text{People who have either or both lunch} \\
n(A\cup B) = \frac{288}{5}+\frac{144}{5}-\frac{72}{5} \\
= \frac{360}{5} = 72
\end{aligned}

So People who do no have either lunch were = 96 -72
= 24

5. Raman's salary was decreased by 50% and subsequently increased by 50%. How much percent does he loss.

Answer: Option D

Explanation:

Let the origianl salary = Rs. 100

It will be 150% of (50% of 100)
= (150/100) * (50/100) * 100 = 75

So New salary is 75, It means his loss is 25%