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 8 of 14.
Ankit said:
10 years ago
Please clear that how come answer?
Nitin said:
9 years ago
20% of student below 8 year. So, 80% of students above and same age.
Number of students of same age = 48.
Number of students of above 8 is 2/3 of 48.
x is total students.
80% of x = 48 + 2/3 of 48.
x = 100.
Number of students of same age = 48.
Number of students of above 8 is 2/3 of 48.
x is total students.
80% of x = 48 + 2/3 of 48.
x = 100.
Pushpi rai said:
9 years ago
Thanks @Vinod Anand.
I understand your explanation.
I understand your explanation.
Priyanka Gupta said:
9 years ago
ALTERNATIVELY:.
Let total nos of student be x.
1) Number of Student below 8 years = 20%of x.
2) Number of Student Above 8 years = 2/3 of 48.
3) Number of Student of 8 years = 48.
So, Total students = 20%of x + 2/3 of 48 + 48.
x = 20/100 * x + 2/3 * 48 + 48.
After solving above equation,
x=100.
Let total nos of student be x.
1) Number of Student below 8 years = 20%of x.
2) Number of Student Above 8 years = 2/3 of 48.
3) Number of Student of 8 years = 48.
So, Total students = 20%of x + 2/3 of 48 + 48.
x = 20/100 * x + 2/3 * 48 + 48.
After solving above equation,
x=100.
Ramesh said:
9 years ago
It clearly indicates that 80% of students is 100 but 100% is 120 must be the answer.
Sam said:
9 years ago
I like your method @Showry.
Sachin Dubey said:
9 years ago
x = total number of students.
Below 8 year = 20%x.
Exact 8 year = 48.
Above 8 year= (2/3) * 48 = 32.
Then the equation becomes (we have to find x):
x = (20%x) + 48 + 32.
x - (20%x) = 80.
100x - 20x = 80 * 100.
x = 100.
Hope you will understand it.
Below 8 year = 20%x.
Exact 8 year = 48.
Above 8 year= (2/3) * 48 = 32.
Then the equation becomes (we have to find x):
x = (20%x) + 48 + 32.
x - (20%x) = 80.
100x - 20x = 80 * 100.
x = 100.
Hope you will understand it.
Neeraj said:
9 years ago
Why we are doing 2/3*48? Please, anyone explain me.
Asad said:
9 years ago
Nice one @Rumman.
Ayesha said:
9 years ago
Nice explanation @Ramesh.
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