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 4 of 14.
DURAI said:
1 decade ago
Total no of students = no.of students below 8 yrs + no.of students exact 8 yrs + no.of students above 8 yrs.
Given data:
no.of students 8 yrs exact = 48.
no.of students above 8 yrs = 2/3 of 48 = 32.
no.of students below 8 yrs = 20.
Answer = 48+32+20 = 100.
Given data:
no.of students 8 yrs exact = 48.
no.of students above 8 yrs = 2/3 of 48 = 32.
no.of students below 8 yrs = 20.
Answer = 48+32+20 = 100.
Krushna said:
3 years ago
Given;
20% below 8 year of age. (100%- 20% ) = 80%.
80 % = age of students equal to 8 yr + age of students above 8 yr.
80 % of Total students = 48 + 2/3 * 48.
80% of Total students = 48+32 = 80
(80/100)* Total students = 80
Total Students = 80 *(100/80) = 100.
20% below 8 year of age. (100%- 20% ) = 80%.
80 % = age of students equal to 8 yr + age of students above 8 yr.
80 % of Total students = 48 + 2/3 * 48.
80% of Total students = 48+32 = 80
(80/100)* Total students = 80
Total Students = 80 *(100/80) = 100.
(20)
Ani said:
6 years ago
For those who are concluding the answer to be 150:
48 is the number of student belonging to 8 years of age, and not the number of students above 8 years of age. This is the confusing part! That's how the answer of total number of students becomes 100.
48 is the number of student belonging to 8 years of age, and not the number of students above 8 years of age. This is the confusing part! That's how the answer of total number of students becomes 100.
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.
Robin Loomba said:
1 decade ago
Total number of students = x.
According to the condition:
20% of student below 8 years + 48 (8 years student) + (2/3)*48 above 8 years = x (total number of students).
20% of x + 48 + 32 = x.
(20/100)*x + 80 = x.
80 = x-x/5.
80 = 4x/5.
x = 100.
According to the condition:
20% of student below 8 years + 48 (8 years student) + (2/3)*48 above 8 years = x (total number of students).
20% of x + 48 + 32 = x.
(20/100)*x + 80 = x.
80 = x-x/5.
80 = 4x/5.
x = 100.
Swathi krishna.b said:
5 years ago
Exact 8 years = 48.
Above 8 years age=2/3*48=32.
Then, 20% of the students below 8 years, so 80% of the students are 48+32=80.
80---------->80
20---------->?.
80 * 20/80==>1600/80=20.
So, the total number of students is 32+48+20=100.
Above 8 years age=2/3*48=32.
Then, 20% of the students below 8 years, so 80% of the students are 48+32=80.
80---------->80
20---------->?.
80 * 20/80==>1600/80=20.
So, the total number of students is 32+48+20=100.
Showry said:
1 decade ago
look this....
Total no of students
S = (age < 8) + (age = 8) + (age > 8)
age < 8 = 20%(S) ====> 20S/100
age = 8 ====> 48
age > 8 ====> (2/3)*48 ====>32
S=20S/100 + 48 +32
S=100
Total no of students
S = (age < 8) + (age = 8) + (age > 8)
age < 8 = 20%(S) ====> 20S/100
age = 8 ====> 48
age > 8 ====> (2/3)*48 ====>32
S=20S/100 + 48 +32
S=100
Sravanreddypailla said:
1 decade ago
Let total=x
exact 8 years = 48
above 8 years = 2/3*48 = 32
so 48+32= 80
given 20% below 8 years therefore reamaining i.e above n exact=80%
from above 80%=80
that means 20%=20(default as we take percentage in hundredths)
TOTAL OF THE ABOVE =100
exact 8 years = 48
above 8 years = 2/3*48 = 32
so 48+32= 80
given 20% below 8 years therefore reamaining i.e above n exact=80%
from above 80%=80
that means 20%=20(default as we take percentage in hundredths)
TOTAL OF THE ABOVE =100
Swathi said:
1 decade ago
Y cant tis be 150??
2/3 of x=48
x=72 is students at age 8
72+48=120 can be equated with 80%
remaining 20% must be added to this.
80%=120
20%=x
x=30
hence total=120+30=150 is total number of students...is tis right???
2/3 of x=48
x=72 is students at age 8
72+48=120 can be equated with 80%
remaining 20% must be added to this.
80%=120
20%=x
x=30
hence total=120+30=150 is total number of students...is tis right???
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.
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