Question Detail

If 2 : 9 :: x : 18, then find the value of x

Answer: Option C

Explanation:

Treat 2:9 as 2/9 and x:18 as x/18, treat :: as =

So we get 2/9 = x/18
=> 9x = 36
=> x = 4

1. A dog takes 3 leaps for every 5 leaps of a hare. If one leap of the dog is equal to 3 leaps of the hare, the ratio of the speed of the dog to that of the hare is

Answer: Option B

Explanation:

Dog : Hare = (3*3) leaps of hare : 5 leaps of hare
= 9 : 5

2. Salaries of Ravi and Sumit are in the ratio 2:3. If the salary of each is increased by Rs 4000, the new ratio becomes 40:57. What is Sumit present salary.

32000
34000
38000
40000

Answer: Option C

Explanation:

Let the original Salaries of Ravi and Sumit is 2x and 3x.

So as per question

\begin{aligned}
\frac{2x+4000}{3x+4000} = \frac{40}{57} \\
=> 57(2x+4000) = 40(3x+4000) \\
=> 6x = 68000 \\
=> 3x = 34000 \\

\text{ Sumit Salary =} 3x+4000 \\
34000 + 4000 = 38000

\end{aligned}

3. There are two numbers and their ratio is 3 : 9. If we substract 9 from both numbers then their ratio becomes 12 : 13, what is value is smaller number ?

Answer: Option D

Explanation:

From question, lets assume that two numbers are 3x and 5x.

\begin{aligned}
\text{then, }\frac{3x - 9}{ 5x - 9} = \frac{12}{23}\\
=> \text{23(3x - 9) = 12(5x - 9)}\\
=> 9x = 99 \\
=> x = 11
\end{aligned}
So numbers are 3(11) = 33, 5(11) = 55.
Smaller number is 33.

4. A and B together have Rs. 1210. If 4/15 of A's amount is equal to 2/5 of B's amount. How much amount B have.

Rs 484
Rs. 480
Rs 478
Rs 470

Answer: Option A

Explanation:

In this type of question, we will first try to calculate the ratio of two persons. Once we get ratio then we can easily get our answer. So lets solve this.

\begin{aligned}
\frac{4}{15}A = \frac{2}{5}B \\
A = \left(\frac{2}{5}*\frac{14}{4}\right)B \\
A = \frac{3}{2}B \\
\frac{A}{B} = \frac{3}{2} \\
A:B = 3:2 \\
\text{B's Share = }\frac{2}{5}*1210 = 484
\end{aligned}

5. Two numbers are respectively 20% and 50% more than a third number. The ratio of the two numbers is

Answer: Option C

Explanation:

Let the third number be x.
First Number (120/100)*x = 6x/5
Second Number (150/100)*x = 3x/2

Ratio = 6x/5:3x/2
=> 4:5