Aptitude - Percentage - Discussion
Discussion Forum : Percentage - General Questions (Q.No. 7)
7.
In a certain school, 20% of students are below 8 years of age. The number of students above 8 years of age is 
of the number of students of 8 years of age which is 48. What is the total number of students in the school?
Answer: Option
Explanation:
Let the number of students be x. Then,
Number of students above 8 years of age = (100 - 20)% of x = 80% of x.
 80% of x = 48 + |
2 | of 48 |
| 3 |
 |
80 | x = 80 |
| 100 |
x = 100.
Video Explanation: https://youtu.be/yPfocU6DA2M
Discussion:
135 comments Page 12 of 14.
Vaibhav said:
7 years ago
Thanks @Ramesh.
Aarthi said:
7 years ago
Thank you @Ramesh.
Vennela said:
7 years ago
Why 2/3*48, it should be 2/3*100 right?
Please clear my doubt.
Please clear my doubt.
M.Suresh said:
7 years ago
1/5*X+48+2/3*48 = X.
1/5*X+48+32 = X,
80 = (5X-X)/5,
80*5 = 4X,
400/4 = X,
100 = X.
1/5*X+48+32 = X,
80 = (5X-X)/5,
80*5 = 4X,
400/4 = X,
100 = X.
Mallikarjun Reddy said:
7 years ago
Well said, Thanks @Ramesh.
Soukhya G M said:
7 years ago
Thank you all for explaining this. I get it now.
Nisha said:
7 years ago
Why add 48 in 80% of x = 48 +2/3of 48?
Please explain this step.
Please explain this step.
Pradeep said:
7 years ago
x students in total,
(100 - 20)% * x = 80% * x.
80/100 * x = 48+(2/3)48,
(80/100)*x=48+32=80,
80% is 80, then 100% of 100.
(100 - 20)% * x = 80% * x.
80/100 * x = 48+(2/3)48,
(80/100)*x=48+32=80,
80% is 80, then 100% of 100.
Arun said:
6 years ago
No answer is 100.
Below 8 years is 20%.
Above 8years is 2/3rd of 48 (48= exact age of 8years).
2/3 rd =32.
So total students is age below 8 exactly 8 and above 8.
=48+32+x,
=80+x.
Below 8 years and exactly 8 years are 80%.
remaining are 20% i.e below 8 years =20.
Which gives 100.
Below 8 years is 20%.
Above 8years is 2/3rd of 48 (48= exact age of 8years).
2/3 rd =32.
So total students is age below 8 exactly 8 and above 8.
=48+32+x,
=80+x.
Below 8 years and exactly 8 years are 80%.
remaining are 20% i.e below 8 years =20.
Which gives 100.
Harish said:
6 years ago
20% is below 8 years.
Then 80% is above 8 and at the age of 8,
80%=48+(2/3 * 48),
80%=80,
Then 100%=100.
Then 80% is above 8 and at the age of 8,
80%=48+(2/3 * 48),
80%=80,
Then 100%=100.
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