Question Detail

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

1. Two numbers are less than third number by 30% and 37% respectively. How much percent is the second number less than by the first

Answer: Option C

Explanation:

Let the third number is x.
then first number = (100-30)% of x
= 70% of x = 7x/10

Second number is (63x/100)

Difference = 7x/10 - 63x/100 = 7x/10

So required percentage is, difference is what percent of first number

=> (7x/100 * 10/7x * 100 )% = 10%

2. How many litres of pure acid are there in 8 litres of a 20% solution

Answer: Option B

Explanation:

Question of this type looks a bit typical, but it is too simple, as below...

It will be 8 * 20/100 = 1.6

3. 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:

4. If number x is 10% less than another number y and y is 10% more than 125, then find out the value of x

123.55
123.65
123.75
123.85

Answer: Option C

5. 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,

$\begin{aligned} \left(\frac{130}{100}x\right) \\ => \frac{7.80}{x}-\frac{7.80}{\frac{130}{100}x} = 3\\ => \frac{7.80}{x}-\frac{780}{130x} = 3 \\ => 390x = 234 \\ => x = 0.6 \\ \text{Actual price was Rs 0.6} \\ \text{Present price per dozen will be} \\ Rs.\left(12*\frac{130}{100}*0.6 \right) \\ = Rs. 9.36 \end{aligned}$