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. 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}

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. 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 %

4. 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

5. 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