Question Detail

Simplfy
b - [b -(a+b) - {b - (b - a+b)} + 2a]

Answer: Option D

Explanation:

b-[b-(a+b)-{b-(b-a+b)}+2a]
=b-[b-a-b-{b-(2b-a)}+2a]
=b-[-a-{b-2b+a}+2a]
=b-[-a-{-b+a}+2a]
=b-[-a+b-a+2a]
=b-[-2a+b+2a]
=b-b
=0

1. Simplify
\begin{aligned} 1+\frac{1}{2}+\frac{1}{4}+\frac{1}{7}+\frac{1}{14}+\frac{1}{28} = ? \end{aligned}

Answer: Option A

Explanation:

By taking LCM we get
=\begin{aligned} \frac{28+14+7+4+2+1}{28}
= \frac{56}{28} = 2\end{aligned}

2. 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.

3. Company workers decided to raise Rs. 3 lakhs by equal contribution from each. Had they contributed Rs. 50 each extra, the contribution would have been Rs. 3.25 lakhs. How many workers were they?

Answer: Option C

Explanation:

N * 50 = (325000 - 300000) = 25000
N = 25000 / 50
= 500

4. 18800 / 470 / 20

Answer: Option B

Explanation:

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

5. In a class free notebooks were distributed among all the children. Each child got notebooks which were one-eighth of the number of children. If number of children been half, then each child would have recieved 16 notebooks in total. Find the total number of books distributed.

Answer: Option B

Explanation:

Let suppose total number of students in class are X.
Then from the question we can conclude it that,
\begin{aligned}
X*\frac{1}{8}X = \frac{X}{2}*16 \\
=> X = 64\\
\text{Total notebooks,} \\
= \frac{1}{8}X^2 \\
= \left( \frac{1}{8} * 64 * 64 \right) \\
= 512
\end{aligned}

Vishal 11 years ago

b-[b-(a+b)-{b-(b-a+b)}+2a]
=b-[b-a-b-{b-(2b-a)}+2a]
=b-[-a-{b-2b+a}+2a]
=b-[-a-{-b+a}+2a]
=b-[-a+b-a+2a]
=b-[-2a+b+2a]
=b-b
=0
arun 12 years ago

when sq bracket will be open, then +2a will be convert into -2a. am i right?