Aptitude - Ratio and Proportion - Discussion
Discussion Forum : Ratio and Proportion - General Questions (Q.No. 6)
6.
The ratio of the number of boys and girls in a college is 7 : 8. If the percentage increase in the number of boys and girls be 20% and 10% respectively, what will be the new ratio?
Answer: Option
Explanation:
Originally, let the number of boys and girls in the college be 7x and 8x respectively.
Their increased number is (120% of 7x) and (110% of 8x).
 |
 |
120 | x 7x |  |
and | |
110 | x 8x | |
| 100 | 100 |
| |
42x | and | 44x |
| 5 | 5 |
 The required ratio = |
|
42x | : | 44x | |
= 21 : 22. |
| 5 | 5 |
Discussion:
61 comments Page 1 of 7.
K.kiran kumar said:
2 decades ago
I can not get that how 120% of 7x and 110% of 8x.
Please someone explain it.
Please someone explain it.
Ramesh said:
1 decade ago
7:8 can also be written as 70:80
120/100*70 = 84
110/100*80 = 88
so,new ratio= 84 : 88
or 42 : 44
or 21 : 22
120/100*70 = 84
110/100*80 = 88
so,new ratio= 84 : 88
or 42 : 44
or 21 : 22
ABHINESH said:
1 decade ago
(7x+0.2*7x)/(8x+0.1*8x)=21:22
SRIPAL S said:
1 decade ago
@Kiran Kumar
note that something we included to get 20%
For example the ratio of the ratio of to boys ages was 5:2
we can write it as 5x : 2x we get exact ratio we will not consider it alone
For that way 7x 8x will appear
then
to covert 20% into no. it will be 20/100
note that the unknown was x
then 20/100x*x
so we take common one x(20/100+1)
so x(20/100+100)
x(120/100)
that was we get 120/100
forget x because that x which is in 7x both are same so we get 120/100*7x
note that something we included to get 20%
For example the ratio of the ratio of to boys ages was 5:2
we can write it as 5x : 2x we get exact ratio we will not consider it alone
For that way 7x 8x will appear
then
to covert 20% into no. it will be 20/100
note that the unknown was x
then 20/100x*x
so we take common one x(20/100+1)
so x(20/100+100)
x(120/100)
that was we get 120/100
forget x because that x which is in 7x both are same so we get 120/100*7x
Sasha said:
1 decade ago
I like ramesh's methods ! thanks a lot :).
Poonma said:
1 decade ago
Ramesh your to good.
Khushboo said:
1 decade ago
Why do we multiply 120% by 7x and 100% by 8x
Why not we simply multiply 20% by 7x and 10% by 8x ?
Please someone explain me.
Why not we simply multiply 20% by 7x and 10% by 8x ?
Please someone explain me.
RAJ said:
1 decade ago
RAMESH very well said. ! keep posting your SHORTCUT method. Its very useful for us. !i search at every discussion. Because of you. !
Priyabrata said:
1 decade ago
20% of 7=14/10,total increase 7+14/10=84/10
10% of 8=8/10,total increase 8+8/10=88/10
now compare ratio of Boys and Girls
84/10:88/10
or 84:88
or 42:44
or 21:22
10% of 8=8/10,total increase 8+8/10=88/10
now compare ratio of Boys and Girls
84/10:88/10
or 84:88
or 42:44
or 21:22
Kavya said:
1 decade ago
I am getting 7:4 by whichever method I do. I am not satisfied with any explanations given. Help me.
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