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 2 of 4.
Rahul v said:
3 years ago
The number of proportional are only in even numbers that's why they are proportional.
(1)
Ramu Kanojiya said:
5 years ago
Thanks all.
(1)
Bii said:
6 years ago
In that case 8/15 and 15/24 are not equal. The answer is 28.
(1)
Manish said:
6 years ago
Product of means = product of extremes.
(1)
Sk.Rahul Basha said:
7 years ago
4th proportion formula.
d = bc/a.
Here. a=5,b=8,c=15,
Now submit in formula.
d=8*15/5=24.
d = bc/a.
Here. a=5,b=8,c=15,
Now submit in formula.
d=8*15/5=24.
(1)
Samim said:
1 decade ago
5:8 = 15:x.
5/8 = 15/x.
5x = 15*8.
x = 90/5.
x =18.
5/8 = 15/x.
5x = 15*8.
x = 90/5.
x =18.
Malli said:
1 decade ago
There is 5:8:15:x then as for formula
1st x 4th=2nd x 3rd
i.e 5*x=8*15(it is a formula)
there four x=24
1st x 4th=2nd x 3rd
i.e 5*x=8*15(it is a formula)
there four x=24
Manik said:
1 decade ago
Is this formula applicable for such other problems? What abt the formula of fifth, sixth or higher proportional?
Sai said:
1 decade ago
Formula must be used compulsory ? we can assume it as in series form as 5, 15, 25, 35.... In same manner 8, 18, 28......
Shrishti said:
1 decade ago
This is solved by proportional formula such as a:b :: c:d
Formula: a*d=b*c (as said find fourth proportional).
Formula: a*d=b*c (as said find fourth proportional).
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