Question Detail

What fraction of \begin{aligned} \frac{4}{7}\end{aligned} should be added to itself to become \begin{aligned} 1\frac{1}{14} \end{aligned}

\begin{aligned} \frac{7}{8} \end{aligned}
\begin{aligned} \frac{7}{9} \end{aligned}
\begin{aligned} \frac{7}{10} \end{aligned}
\begin{aligned} \frac{7}{11} \end{aligned}

Answer: Option A

Explanation:

\begin{aligned}
=> \frac{4}{7}x + \frac{4}{7} = \frac{15}{4}
\end{aligned}
\begin{aligned}
= \frac{4}{7}x = \frac{15}{4} - \frac{4}{7}
\end{aligned}
\begin{aligned}
= \frac{4}{7}x = \frac{7}{14}
\end{aligned}
\begin{aligned}
= x = \frac{1}{2}\times \frac{7}{4} = \frac{7}{8}
\end{aligned}

1. Value of \begin{aligned} 2^5 \times 9^2 \end{aligned} has been written as 2596, what is the difference between actual value.

Answer: Option D

2. 18800 / 470 / 20

Answer: Option B

Explanation:

18800 / 470 / 20 = (18800 / 470) / 20 = 40 / 20 = 2

3. The number of girls in a class are 7 times the number of boys, which value can never be the of total students

Answer: Option D

Explanation:

Let the boys are X, then girls are 7X, total = X+7X = 8X

So it should be multiple of 8, 30 is not a multiple of 8.

4. Simplify
\begin{aligned}
16-[5-(6+2(7-\overline{8-5}))]
\end{aligned}

Answer: Option B

Explanation:

\begin{aligned}
= 16-[5-(6+2(7-8+5))]
\end{aligned}
(Please check due to overline, sign has been changed)
\begin{aligned}
= 16-[5-(6+2 \times 4))]
\end{aligned}
\begin{aligned}
= 16-[-9] = 16 + 9 = 25
\end{aligned}