Question Detail

Total number of boys and girls in a school is 150. If the number of boys is x, then girls become x% of the total number of students. The number of boys is

Answer: Option B

Explanation:

Clearly,
x% of 150 = 150 - x [as x is number of boys]

\begin{aligned}
=> x + \frac{x}{100} * 150 = 150 \\

=> \frac{5}{2}x = 150 \\

=> x = 60 \\
\end{aligned}

1. How many litres of pure acid are there in 8 litres of a 20% solution

Answer: Option B

Explanation:

Question of this type looks a bit typical, but it is too simple, as below...

It will be 8 * 20/100 = 1.6

2. The ratio 5:20 expressed as percent equals to

50 %
125 %
25 %
None of above

Answer: Option C

Explanation:

Actually it means 5 is what percent of 20, which can be calculated as,
(5/20)*100 = 5 * 5 = 25

3. Half of 1 percent written as decimal is

5
0.5
0.05
0.005

Answer: Option D

Explanation:

It will be 1/2(1%) = 1/2(1/100) = 1/200 = 0.005

4. 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 %