Question Detail

10% of inhabitants of a village having died of cholera, a panic set in, during which 25% of the remaining inhabitants let the village. The population is then reduced to 4050. Find the original inhabitants

5500
6000
6500
7000

Answer: Option B

Explanation:

Let the total number is x,
then,

(100-25)% of (100 - 10)% x = 4050
=> 75% of 90% of x = 4050
=> 75/100 * 90/100 * x = 4050
=> x = (4050*50)/27 = 6000

1. 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.

2. What will be the fraction of 20%

1/4
1/5
1/10
None of above

Answer: Option B

Explanation:

It will 20*1/100 = 1/5

3. In expressing a length of 81.472 km as nearly as possible with the three significant digits, find the percentage error

0.35%
0.34%
0.034%
0.035%

Answer: Option C

Explanation:

Error = (81.5 - 81.472) = 0.028
Required percentage = \begin{aligned}
\frac{0.028}{81.472} \times 100 = 0.034 %
\end{aligned}

4. In an examination, 34% of the students failed in mathematics and 42% failed in English. If 20% of the students failed in both the subjects, then find the percentage of students who passed in both the subjects.

Answer: Option C

Explanation:

Failed in mathematics, n(A) = 34
Failed in English, n(B) = 42
\begin{aligned}
n(A\cup B) = n(A)+n(B)-n(A\cap B) \\
= 34+42-20 = 56 \\
\text{Failed in either or both subjects are 56} \\
\text{Percentage passed = }(100-56)\% \\
= 44\%
\end{aligned}

5. If sales tax is reduced from 5% to 4%, then what difference it will make if you purchase an item of Rs. 1000

Answer: Option A

Explanation:

Clue: Answer will be 5% of 1000 - 4% of 1000