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 1 of 13.
Mona said:
2 decades ago
Explain how 8*3/5 came ?
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
Mukesh said:
1 decade ago
How do we take 3:5 and why.
Explain how 8*3/5 came ? and why.
Explain how 8*3/5 came ? and why.
Kalpa said:
1 decade ago
Let 3 number are X,Y,Z
given X+Y+Z=98
X:Y::2:3 Y:Z::5:8
=> X/Y=2/3 =>Y/Z=5/8
=> X=2Y/3 =>Z=8Y/5
so,X+y+z=98
=>2Y/3+y+8Y/5=98
=>(10Y+15Y=24Y)/15=98
=>Y=1470/49
=>Y=30
so,2nd no. is 30.
given X+Y+Z=98
X:Y::2:3 Y:Z::5:8
=> X/Y=2/3 =>Y/Z=5/8
=> X=2Y/3 =>Z=8Y/5
so,X+y+z=98
=>2Y/3+y+8Y/5=98
=>(10Y+15Y=24Y)/15=98
=>Y=1470/49
=>Y=30
so,2nd no. is 30.
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
Karthik said:
1 decade ago
Hi aparn.
Its very easy to understand. Thank you.
Its very easy to understand. Thank you.
Daksh said:
1 decade ago
Explain how B=(98*15/49) ?
Aparna said:
1 decade ago
Look at the ratio:
10:15:24
here B's part is 15
and this 15 is out of 49(10+15+24)
just mutiply (15/49) by 98
to get the actual value of B
10:15:24
here B's part is 15
and this 15 is out of 49(10+15+24)
just mutiply (15/49) by 98
to get the actual value of B
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)....
Babu said:
1 decade ago
Excellent Kalpa
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