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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 ?

  • 23
  • 27
  • 31
  • 33

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.

Similar Questions :

1. if x:y = 1:3, then find the value of
(7x+3y):(2x+y)

  • 14:5
  • 15:5
  • 16:5
  • 17:5

Answer: Option C

Explanation:

let x = 1k and y = 3k, so
\begin{aligned}
= \frac{7(k)+3(3k)}{2(k)+1(3k)} \\
= \frac{16k}{5k} \\
= 16:5
\end{aligned}

2. If 40% of a number is equal to two-third of another number, what is the ratio of first number to the second number.

  • 2:5
  • 2:7
  • 5:7
  • 5:3

Answer: Option D

Explanation:

Let the first number is A and second number is B.

As per question

\begin{aligned}
\frac{40}{100}A = \frac{2}{3}B \\

\frac{A}{B} = \frac{2}{3}*\frac{100}{40} \\
\frac{A}{B} = \frac{5}{3} \\
=> A:B = 5:3

\end{aligned}

3. If Rs. 782 is divided into three parts, proportional to
\begin{aligned}
\frac{1}{2}:\frac{2}{3}:\frac{3}{4}
\end{aligned}

find the first part.

  • 190
  • 204
  • 220
  • 230

Answer: Option B

Explanation:

\begin{aligned}
\frac{1}{2}:\frac{2}{3}:\frac{3}{4} \\
= 6:8:9\\
\text{First part =} 782 * \frac{6}{23} \\
= 204
\end{aligned}

4. In a college, the ratio of the number of boys to girls is 8 : 5. If there are 200 girls, the total number of students in the college is

  • 420
  • 520
  • 620
  • 720

Answer: Option B

Explanation:

Let the boy are 8x and Girls are 5x

=> 5x = 200
=> x = 40

Total students = 8x+5x = 13x = 13(40) = 520

5. In a mixture 60 litres, the ratio of milk and water 2 : 1. If the this ratio is to be 1 : 2, then the quanity of water to be further added is

  • 20 liters
  • 30 liters
  • 50 liters
  • 60 liters

Answer: Option D

Explanation:

Quantity of Milk = 60*(2/3) = 40 liters
Quantity of water = 60-40 = 20 liters

As per question we need to add water to get quantity 2:1

=> 40/(20+x) = 1/2
=> 20 + x = 80
=> x = 60 liters

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