Aptitude - Ratio and Proportion - Discussion

Discussion Forum : Ratio and Proportion - General Questions (Q.No. 9)
9.
The sum of three numbers is 98. If the ratio of the first to second is 2 :3 and that of the second to the third is 5 : 8, then the second number is:
20
30
48
58
Answer: Option
Explanation:

Let the three parts be A, B, C. Then,

A : B = 2 : 3 and B : C = 5 : 8 = 5 x 3 : 8 x 3 = 3 : 24
5 5 5

A : B : C = 2 : 3 : 24 = 10 : 15 : 24
5

B = 98 x 15 = 30.
49

Discussion:
122 comments Page 6 of 13.

Sana said:   1 decade ago
Kalpa and Abhishek gave best n easy methods, thank you :).

Amruta said:   1 decade ago
Thanks kalpana:).

PravinBabu said:   1 decade ago
Excellent Alisha

Nena said:   1 decade ago
I have a question please solve it. If A:B=2:3, B:C=4:5, and C:D= 6:7 then find the value of A:B:C:D.

Rupam said:   1 decade ago
A:B = 2:3.
B:C = 5:8.

(2:3)x5 = 10:15.
(5:8)x3 = 15:24.

A:B:C = 10:15:24.
So the second number(B) is: (98*15/49) = 30.

Sid said:   1 decade ago
@jay namdev we have Rs.58.

IN 58 25 paise is = 58*4 = 232.
In 58 50 paise is = 58*2 = 116.

Ratio of 50 paise : 25 paise 1:2.
Total 150 student it means if boys is 50 then girls is 100.
100+50 =150.

It means total girls in class is 100.

Elizabeth Scaria said:   1 decade ago
If a:b=m:n and b:c=p:q then a:b:c= mp:np:nq.

Here,

a:b=2:3 .
b:c=5:8.

Then a:b:c become 10:15:24.

If sum of money S is divided in the ratio a:b:c then part of b is

= (b/a+b+c)*S.

Now here part of B become (15/49)*98 = 30.

Chandan said:   1 decade ago
A:B = 2:3.
B:C = 5:8.

(2:3)x5 = 10:15.
(5:8)x3 = 15:24.

A:B:C = 10:15:24.

Let the ratio of numbers be 10x:15x:24x.

According to question,

10x+15x+24x = 98.

49x = 98.

x = 98/49.

x = 2.

Now 2nd number is 15x.

i.e;15*2 = 30.

Divi said:   1 decade ago
Explain the whole problem clearly and step by step.

Vinni said:   1 decade ago
A:B = 2:3.
B:C = 5:8.

By short cut we get,
A:B:C = 10:15:24.

How we get is by using above ratios,

A's value = A*B.
B = B*B.
C = B*C...

Then as given in problem,

10x+15x+24x = 98.
49x = 98.
x = 2..

So, 15x = 15*2 = 30.


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