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:
137 comments Page 8 of 14.
Aarthy said:
8 years ago
As specified by the question, we can rewrite it as x= 20/100*x+48+2/3 (48). Where x be the total number of students in the school and by solving the above expression, we get the answer as 100.
That's all. Simple.
That's all. Simple.
Abhishek said:
8 years ago
Let the total no of students be =x.
Then 20% of student are below 8 years, means x *20/100 =x/5 --------> eqn 1
Now 48 student are 8 years old --------> eqn2.
And no of the student which is above 8 years is 2/3 of 48 ie 32 --------> eqn3.
So by eqn 2 and 3 by addition 48+32=80.
So we add 20 more to make it 100 so answer is 100.
Then 20% of student are below 8 years, means x *20/100 =x/5 --------> eqn 1
Now 48 student are 8 years old --------> eqn2.
And no of the student which is above 8 years is 2/3 of 48 ie 32 --------> eqn3.
So by eqn 2 and 3 by addition 48+32=80.
So we add 20 more to make it 100 so answer is 100.
Deepan said:
8 years ago
Hi, According to me,
We are calculating upto 80% and what about remaining 20%?
So, [80%+20%]=[100+25],
No.of students = 125.
We are calculating upto 80% and what about remaining 20%?
So, [80%+20%]=[100+25],
No.of students = 125.
Santosh shah said:
8 years ago
Below 8 year= 20,
Exact 8 year= 48,
Above 8 year = 2/3 * 48 = 32.
So, total students=100.
Exact 8 year= 48,
Above 8 year = 2/3 * 48 = 32.
So, total students=100.
Lavanya said:
8 years ago
@Ramesh.
They mentioned 20%.
Is that right to mention it as simply 20?
They mentioned 20%.
Is that right to mention it as simply 20?
Md jakir hossain said:
9 years ago
Thanks for the given explanation.
Ramasubramanian said:
9 years ago
Very good explanation @Ramesh.
Rehan said:
9 years ago
Thanks for explaining the solution.
Anshra Khan said:
9 years ago
Good and easy method @Ramesh. Thanks.
RAJIB KUMAR KOHAR said:
9 years ago
Students at the age of 8 = 48,
Students above age of 8 = 2/3 of 48 = 32,
Students at the age of 8 = 20,
Total students = (48 + 32 + 20) = 100.
Students above age of 8 = 2/3 of 48 = 32,
Students at the age of 8 = 20,
Total students = (48 + 32 + 20) = 100.
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