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:
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 2 of 13.
Rithesh said:
1 decade ago
See @mona
Here actually we use to find the ratio is the the ratio between c:a
Beacause already a:b & b:c are given
to find c:a
here we got 3:5 by
by taking the last digit in the ratio a:b 2:3 we took 3
by taking the first digit in the ratio b:c 5:8 we took 5
then mulltiply the
ratio numbers in b:c with 3/5 then we will get
Here actually we use to find the ratio is the the ratio between c:a
Beacause already a:b & b:c are given
to find c:a
here we got 3:5 by
by taking the last digit in the ratio a:b 2:3 we took 3
by taking the first digit in the ratio b:c 5:8 we took 5
then mulltiply the
ratio numbers in b:c with 3/5 then we will get
Preethi said:
4 months ago
A : B = 2 : 3
B:C = 5:8
Given, A + B + C = 98.
A : B = 2 : 3
B : C = 5 : 8
Now, A : B : C = (2 * 5) : (5 * 3) : (3 * 8),
= 10 : 15 : 24.
The sum of these numbers is 49 which is not equal to 98. So multiple ratio with 2.
(10 : 15 : 24) * 2 = 20 : 30 : 48.
The sum of these numbers is 98.
Therefore 2nd number is 30.
B:C = 5:8
Given, A + B + C = 98.
A : B = 2 : 3
B : C = 5 : 8
Now, A : B : C = (2 * 5) : (5 * 3) : (3 * 8),
= 10 : 15 : 24.
The sum of these numbers is 49 which is not equal to 98. So multiple ratio with 2.
(10 : 15 : 24) * 2 = 20 : 30 : 48.
The sum of these numbers is 98.
Therefore 2nd number is 30.
(19)
Ayush Jain said:
9 years ago
Given,
A : B : C = 98.
A : B = 2 : 3 ---------------> Eq.1.
B : C = 5 : 8 ---------------> Eq.2.
Now Multiply Eq.1 by 5 and Eq.2 by 3 to get B common;
Then,
A : B = 10 : 15.
B : C = 15 : 24.
Then, A : B : C = 10 : 15 : 24.
So, 10X + 15X + 24X = 98.
49X = 98.
X = 2.
Then, the Second Number is 15X.
i.e B = 15 * 2 = 30 => Ans.
A : B : C = 98.
A : B = 2 : 3 ---------------> Eq.1.
B : C = 5 : 8 ---------------> Eq.2.
Now Multiply Eq.1 by 5 and Eq.2 by 3 to get B common;
Then,
A : B = 10 : 15.
B : C = 15 : 24.
Then, A : B : C = 10 : 15 : 24.
So, 10X + 15X + 24X = 98.
49X = 98.
X = 2.
Then, the Second Number is 15X.
i.e B = 15 * 2 = 30 => Ans.
S.Narayana said:
8 years ago
We have 2:3 & 5:8 but in this question, they only three numbers are there so that let us take a,b,c.
2
3-a
5-b
8-c
So that 3+5+8=16.
16 = 98.
5 = ?.
5 * 98/16 = 30approx.
2
3-a
5-b
8-c
So that 3+5+8=16.
16 = 98.
5 = ?.
5 * 98/16 = 30approx.
Nandita Bhoyar said:
4 years ago
We can try a simpler method:
Let the three numbers be x,y, and z.
It's given that,
x+y+z = 98 --------> (i)
Now, x/y = 2/3
So, x = 2y/3
And, y/z = 5/8
So, z = 8y/5.
Now putting the values of x and z in (i), we get
2y/3+y+8y/5 = 98,
(10y + 15y + 24y)/15 = 98,
49y/15 = 98,
49y = 1470,
y = 30.
Let the three numbers be x,y, and z.
It's given that,
x+y+z = 98 --------> (i)
Now, x/y = 2/3
So, x = 2y/3
And, y/z = 5/8
So, z = 8y/5.
Now putting the values of x and z in (i), we get
2y/3+y+8y/5 = 98,
(10y + 15y + 24y)/15 = 98,
49y/15 = 98,
49y = 1470,
y = 30.
(22)
Swagger said:
1 decade ago
The easiest way:
a:b:c.
2:3.
5:8.
So 8/5 = 1.6. So c is 1.6 times bigger than b.
So 3*1.6 = 24/5.
Therefore, the ratio is 2:3:24/5.
Simplifying gives ratio as 10:15:24.
To solve the question 10x:15x:24x = 98.
10x+15x+24x = 98,
So 49x = 98, x=2.
Therefore the second number is 15*2 = 30.
a:b:c.
2:3.
5:8.
So 8/5 = 1.6. So c is 1.6 times bigger than b.
So 3*1.6 = 24/5.
Therefore, the ratio is 2:3:24/5.
Simplifying gives ratio as 10:15:24.
To solve the question 10x:15x:24x = 98.
10x+15x+24x = 98,
So 49x = 98, x=2.
Therefore the second number is 15*2 = 30.
Srushti Nijampurkar said:
6 years ago
Let 3 no. be A,B,C
Given:-
A:B = 2:3 ---> (1)
B:C = 5:8 ---> (2)
Multiple 1st No by 5.
Multiple 2nd No by 3.
New values be:-
A:B = 10:15
B:C = 15:24.
It means :-
A:B:C = 10:15:24.
Now B =(98*15/49). [Where 98 is given, 15 is B's value and 49 is the addition of total no]
Then B = 30.
Given:-
A:B = 2:3 ---> (1)
B:C = 5:8 ---> (2)
Multiple 1st No by 5.
Multiple 2nd No by 3.
New values be:-
A:B = 10:15
B:C = 15:24.
It means :-
A:B:C = 10:15:24.
Now B =(98*15/49). [Where 98 is given, 15 is B's value and 49 is the addition of total no]
Then B = 30.
Abhishek said:
1 decade ago
Now,the most easiest and trick method can be:
See, 2:3 and 5:8 are the ratios of First:Second and Second:Third,
So,the Second No. should be a multiple of 3 and 5.So,3*5=15,
Now, choose among the choices of answers,the correct one is [B]30.
30 is the multiple of 15(both 3 and 5)....
See, 2:3 and 5:8 are the ratios of First:Second and Second:Third,
So,the Second No. should be a multiple of 3 and 5.So,3*5=15,
Now, choose among the choices of answers,the correct one is [B]30.
30 is the multiple of 15(both 3 and 5)....
Aparna said:
1 decade ago
Here's the simple method
Solve it by using scaling method
A B C
2 3
5 8
find the lcm of middle term,i:e 5 and 3.its 15
in order to get 15,look at upper part,3 is reqd. to be mutiplied by 5,and 5 by 3 in lower part
A B C
2 3(5)
5(3) 8
ans:
2*5:3*5:8*3
10:15:24
Solve it by using scaling method
A B C
2 3
5 8
find the lcm of middle term,i:e 5 and 3.its 15
in order to get 15,look at upper part,3 is reqd. to be mutiplied by 5,and 5 by 3 in lower part
A B C
2 3(5)
5(3) 8
ans:
2*5:3*5:8*3
10:15:24
Shipra said:
1 decade ago
Hello guys!
There is a short trick for these kinds of questions.
Given,
A:B = 2:3.
B:C = 5:8.
Multiply A and B (below one) , B and B (below one) and lastly B and C (below one).
We directly get 10:15:24.
Now add them all i.e. (10+15+24) = 49.
From formula,
(98*15)/49 = 30.
There is a short trick for these kinds of questions.
Given,
A:B = 2:3.
B:C = 5:8.
Multiply A and B (below one) , B and B (below one) and lastly B and C (below one).
We directly get 10:15:24.
Now add them all i.e. (10+15+24) = 49.
From formula,
(98*15)/49 = 30.
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