Question Detail

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
$\begin{aligned} = \frac{7(k)+3(3k)}{2(k)+1(3k)} \\ = \frac{16k}{5k} \\ = 16:5 \end{aligned}$

1. If a:b = 2:3 and b:c = 4:3, then find a:b:c

8:12:9
2:3:8
2:3:9
2:3:12

Answer: Option A

Explanation:

$\begin{aligned} a:b = 2:3 \\ b:c = 4:3 = (4*\frac{3}{4} : 3*\frac{3}{4}) \\ = 3:\frac{9}{4} \\ a:b:c = 2:3:\frac{9}{4} \\ = 8:12:9 \end{aligned}$

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. The sum of three numbers is 98. If the ratio of the first to the second is 2:3 and that of the second to the third is 5:8, then the second number is

Answer: Option D

Explanation:

$\begin{aligned} a:b = 2:3 \\ b:c = 5:8 = (5*\frac{3}{5} : 8*\frac{3}{5}) \\ = 3:\frac{24}{5} \\ a:b:c = 2:3:\frac{24}{5} \\ = 10:15:24 \\ b = 98*\frac{15}{49} \\ = 30 \end{aligned}$

4. If A:B = 2:3, B:C = 4:5 and C:D = 6:7, then find the value of A:B:C:D

15:24:30:35
16:24:30:35
17:24:30:35
18:24:30:35

Answer: Option B

Explanation:

$\begin{aligned} A:B = 2:3 \\ B:C = 4:5 = (4*\frac{3}{4} : 5*\frac{3}{4}) \\ = 3:\frac{15}{4} \\ C:D = 6:7 = (6*\frac{15}{24} : 7*\frac{15}{24}) \\ = \frac{15}{4}:\frac{35}{8} \\ A:B:C:D = 2:3:\frac{15}{4}:\frac{35}{8} \\ = 16:24:30:35 = 8:12:9 \end{aligned}$

5. The least whole number which when subtracted from both the terms of the ratio 6 : 7 to give a ratio less than 16 : 21, is

Answer: Option A

Explanation:

Let x is subtracted.
Then,
$\begin{aligned} \frac{(6-x)}{(7-x)}< \frac{16}{21} \\ 21(6—x) < 16(7—x)\\ => 5x > 14 = x > 2.8 \end{aligned}$

Least such number is 3