Aptitude - Ratio and Proportion - Discussion
Discussion Forum : Ratio and Proportion - General Questions (Q.No. 13)
13.
The fourth proportional to 5, 8, 15 is:
Answer: Option
Explanation:
Let the fourth proportional to 5, 8, 15 be x.
Then, 5 : 8 : 15 : x
5x = (8 x 15)
| x = | (8 x 15) | = 24. |
| 5 |
Discussion:
34 comments Page 3 of 4.
Reethrose said:
1 decade ago
5:8::15:?
5*3=15
8*3=24
so the answer is 24.
5*3=15
8*3=24
so the answer is 24.
Priyankapatil said:
1 decade ago
How to find fifth proportional?
Azeem said:
1 decade ago
Assume a=5, b=8, c=15.
We all know the ad = bc.
a = bc/d, b = ad/c, c = ad/b.
Simillarly d = bc/a.
So 8*15/5 => 120/5 = 24.
We all know the ad = bc.
a = bc/d, b = ad/c, c = ad/b.
Simillarly d = bc/a.
So 8*15/5 => 120/5 = 24.
Divya said:
1 decade ago
Let the 4th proportional to 5:8::15:x.
Product of extremes = product of means.
5x = 8*15.
x = 120/5.
= 24.
Product of extremes = product of means.
5x = 8*15.
x = 120/5.
= 24.
Hanson said:
1 decade ago
Better still:
It will be split this way: 5:8=> 15:x.
Hence, the common factor is 15/5 = 3.
Thus, x/8 = 3.
x= 8*3 =24.
It will be split this way: 5:8=> 15:x.
Hence, the common factor is 15/5 = 3.
Thus, x/8 = 3.
x= 8*3 =24.
Sasulya said:
9 years ago
Just see diff. between 3 numbers and all are odd.
5 and 8 = 3 odd number.
8 and 15 = 7 odd number.
Then next odd num after 7 is 9.
5 and 8 = 3 odd number.
8 and 15 = 7 odd number.
Then next odd num after 7 is 9.
Shipra said:
1 decade ago
Hello guys!
Its given,
5:8:15:x.
Where we take x as constant.
Now,
5/8 = 15/x.
=> 5 = (15*8)/x.
On cross multiplication we get,
x = (15*8)/5.
x = 3*8.
x = 24.
Its given,
5:8:15:x.
Where we take x as constant.
Now,
5/8 = 15/x.
=> 5 = (15*8)/x.
On cross multiplication we get,
x = (15*8)/5.
x = 3*8.
x = 24.
Sumitra said:
1 decade ago
It should be like this 5:8::15:x.
Then 5/8 = 15/x.
x = 15*8/5.
x = 24.
Then 5/8 = 15/x.
x = 15*8/5.
x = 24.
Isaacs nyondo said:
10 years ago
It is really supposed to be.
5:8 = 15:x.
It means that they are terms of a sequence.
Then:
5/8 =15/x.
x = 15*8/5.
x = 24.
5:8 = 15:x.
It means that they are terms of a sequence.
Then:
5/8 =15/x.
x = 15*8/5.
x = 24.
Main said:
10 years ago
It should be 8x15 = 90.
5 then the answer is 18 because 90/5 = 18.
5 then the answer is 18 because 90/5 = 18.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers