Question Detail

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}

1. Rs. 120 are divided among A, B, C such that A's share is Rs. 20 more than B's and Rs. 20 less than C's. What is B's share

Rs 10
Rs 20
Rs 24
Rs 28

Answer: Option B

Explanation:

Let C = x. Then A = (x—20) and B = (x—40).
x + x - 20 + x - 40 = 120 Or x=60.
A:B:C = 40:20:60 = 2:1 :3.
B's share = Rs. 120*(1/6) = Rs. 20

2. Find the fourth proportion to 2,3,6

Answer: Option C

Explanation:

2:3 :: 6:x

=> 2/3 = 6/x
=> x = 18/2
=> x = 9

3. 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

4. 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

5. 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

Bhavini Sumati 9 years ago

Plz explain why have you divided by 3/4 and 15/24 in the question, "
If A:B = 2:3, B:C = 4:5 and C:D = 6:7, then find the value of A:B:C:D" ? Please tell.

nilesh 8 years ago replied

simple method 2*4*6:3*4*6:3*5*6:3*5*7