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 2 of 14.
JPE said:
2 years ago
No.of students of 8 yrs - 48.
No.of students of above 8 yrs - 2/3 of 8 yrs old stud.
So, 2/3*48 = 32.
Total students of 8 yrs and above 8 yrs = 48 + 32 = 80 students.
Now, out of the total students, only 20% of them are below 8 years old. We don't know how many are total students yet. So let's assume the total students as X.
Students below 8 years old -X*20/100(20% is written as 20/100).
= 20x/100.
Total students in school,
80(8yr & above 8 yr total) + 20x/100(below 8yrs total) = x(total students in school that we assumed as x).
80 + 20x/100 = x.
//Take LCM for 80+20x/100.
(8000+20x)/100 = x.
//Bring the denominator 100 to the right side to multiply with x.
8000 + 20x = 100x.
8000 = 80x.
x = 100.
No.of students of above 8 yrs - 2/3 of 8 yrs old stud.
So, 2/3*48 = 32.
Total students of 8 yrs and above 8 yrs = 48 + 32 = 80 students.
Now, out of the total students, only 20% of them are below 8 years old. We don't know how many are total students yet. So let's assume the total students as X.
Students below 8 years old -X*20/100(20% is written as 20/100).
= 20x/100.
Total students in school,
80(8yr & above 8 yr total) + 20x/100(below 8yrs total) = x(total students in school that we assumed as x).
80 + 20x/100 = x.
//Take LCM for 80+20x/100.
(8000+20x)/100 = x.
//Bring the denominator 100 to the right side to multiply with x.
8000 + 20x = 100x.
8000 = 80x.
x = 100.
(15)
Vaibhav kumar singh said:
3 years ago
If 20 % = above 8 years so , 80 % = below 8 years + exact 8 years.
therefore 80 % ----> 2/3 of 48=32 (below 8 years) + 48(exact).
80% ---------> 80.
100% ---------> 100.
So, ans = 100.
therefore 80 % ----> 2/3 of 48=32 (below 8 years) + 48(exact).
80% ---------> 80.
100% ---------> 100.
So, ans = 100.
(14)
Gokulavasan said:
2 years ago
Below 8 years is 20%.
Above 8 and equal to 8 years is 80%.
The number of students above 8 years of age is 2/3 of the number of students of 8 years of age which is 48.
1/3 of 48 students is 16.
2/3 of the students are 32.
1/3+2/3 = 48 (8 years).
16 students (above 8 years),
48 + 32 = 80 equal and above 8 years,
80% = 80 then,
20% = 20.
Total 100 students.
Above 8 and equal to 8 years is 80%.
The number of students above 8 years of age is 2/3 of the number of students of 8 years of age which is 48.
1/3 of 48 students is 16.
2/3 of the students are 32.
1/3+2/3 = 48 (8 years).
16 students (above 8 years),
48 + 32 = 80 equal and above 8 years,
80% = 80 then,
20% = 20.
Total 100 students.
(13)
Prasanth Shanmugam said:
2 years ago
@All.
Here is my solution.
Total Number of Students = X.
Less than 8 Years age Students = 20 % of X = (20/100) * X.
8 Years Age Students = 48,
c = (2/3) * 48 = 32.
Total Number of Students = X = Less than 8 Years age Students + 8 Years Age Students + 8 Years Age Students
X = (20/100) * X + 48+32.
X = (20/100) * X + 80.
X = (20X+8000)/100.
100X = 20X+8000.
80X = 8000.
X = 8000/80.
Total Number of Students = X= 100.
Here is my solution.
Total Number of Students = X.
Less than 8 Years age Students = 20 % of X = (20/100) * X.
8 Years Age Students = 48,
c = (2/3) * 48 = 32.
Total Number of Students = X = Less than 8 Years age Students + 8 Years Age Students + 8 Years Age Students
X = (20/100) * X + 48+32.
X = (20/100) * X + 80.
X = (20X+8000)/100.
100X = 20X+8000.
80X = 8000.
X = 8000/80.
Total Number of Students = X= 100.
(12)
Abel lula shonk said:
2 years ago
Thank you everyone.
(9)
RAMESH said:
1 decade ago
Below 8 years = 20
Exact 8 years = 48
Above 8 years = 2/3*48 = 32
TOTAL OF THE ABOVE =100
Exact 8 years = 48
Above 8 years = 2/3*48 = 32
TOTAL OF THE ABOVE =100
(6)
SAPNA said:
8 years ago
Let a total number of the student be 100% out of which 20% of students are below 8years of age so remaining 80% of students are either 8years of age or above 8years of age.
No of students of 8years age=48(given)
No of students above 8years age=2/3* no of students of 8years age
= 2/3*48,
= 32.
80% of students= no of students of 8years age + no of student above 8years age.
80% of students=48+32,
=80.
(We have to find total students in the school so)
100% of students=80/80*100.
=100.
Total number of students in the school are 100.
No of students of 8years age=48(given)
No of students above 8years age=2/3* no of students of 8years age
= 2/3*48,
= 32.
80% of students= no of students of 8years age + no of student above 8years age.
80% of students=48+32,
=80.
(We have to find total students in the school so)
100% of students=80/80*100.
=100.
Total number of students in the school are 100.
(3)
Pankaj khati uk 01 said:
3 years ago
No of students above 8 years is 48*2/3 =32,
Then let the total number of students = x,
Then 20%of x is = 20* X /100 = x/5,
Than 48 +32+x/5 = x,
Than x = 100.
Then let the total number of students = x,
Then 20%of x is = 20* X /100 = x/5,
Than 48 +32+x/5 = x,
Than x = 100.
(3)
Amal said:
5 months ago
I think 120 is correct.
(3)
Mallepu Naveen Kumar said:
3 years ago
>8yrs = 2/3of 48(8yrs)=> 32students.
8yrs = 48students.
<8yrs = 20%.
80% = (32+48) = 80students,
100% = ?.
Total students = 100/80*80 = 100 students.
8yrs = 48students.
<8yrs = 20%.
80% = (32+48) = 80students,
100% = ?.
Total students = 100/80*80 = 100 students.
(2)
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