Question Detail

If x% of y is 100 and y% of z is 200, then find the relation between x and z.

z = x
2z = x
z = 2x
None of above

Answer: Option C

Explanation:

It is , y% of z = 2(x% of y)
=> yz/100 = 2xy/100
=> z = 2x

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. 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. Due to an increase in 30% in the price of eggs, 3 eggs less are available for Rs. 7.80. Find the present rate of eggs per dozen.

Rs. 9.36
Rs. 10.36
Rs. 11.36
Rs. 12.36

Answer: Option A

Explanation:

Let the original price per egg be Rs x
Then increased price will be,
\begin{aligned}
\left(\frac{130}{100}x\right) \\
=> \frac{7.80}{x}-\frac{7.80}{\frac{130}{100}x} = 3\\
=> \frac{7.80}{x}-\frac{780}{130x} = 3 \\
=> 390x = 234 \\
=> x = 0.6 \\

\text{Actual price was Rs 0.6} \\
\text{Present price per dozen will be} \\
Rs.\left(12*\frac{130}{100}*0.6 \right) \\
= Rs. 9.36
\end{aligned}