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.
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)
S. Raghu yadav said:
4 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 % = 48 + 2/3 * 48.
48 + 32 = 80 students,
80 % = 80 students,
20 % = x students.
Cross multiple;
We get 20 students,
For 20% students = 20 students,
Hence 20 % + 80 % = 20 + 80 students,
Total no of students = 100 students.
20% below 8 year of age. (100%- 20% ) = 80%.
80 % = age of students equal to 8 yr + age of students above 8 yr.
80 % = 48 + 2/3 * 48.
48 + 32 = 80 students,
80 % = 80 students,
20 % = x students.
Cross multiple;
We get 20 students,
For 20% students = 20 students,
Hence 20 % + 80 % = 20 + 80 students,
Total no of students = 100 students.
(1)
Subham Paul said:
3 years ago
1. Let us assume the total number of students be 100%.
2. Then subtract 20% from 100% (where 20% equals less than 8 yrs).
3. Given exact 8 years child = 48.
4. A/Q above 8 years will be 2/3 of 8 years which means (2/3'-48=32).
5. Add exact 8yrs+above 8yrs =80 which is also equal to 80'.
6. Then 100 Will be 80'-100/80=100 students (Total).
2. Then subtract 20% from 100% (where 20% equals less than 8 yrs).
3. Given exact 8 years child = 48.
4. A/Q above 8 years will be 2/3 of 8 years which means (2/3'-48=32).
5. Add exact 8yrs+above 8yrs =80 which is also equal to 80'.
6. Then 100 Will be 80'-100/80=100 students (Total).
(1)
Ashish Kumar Biswas said:
8 years ago
Let,
Total number of student = x.
Given as,
8 years age = 48
8 years above age = 48 *(2/3)
= 32.
Below 8 years age = x*20%
By condition,
X*20%+32+48 = x
Or, x*(20÷100) +80 = x
Or, x - x/5 =80
Or, (5x-x)/5 = 80
Or,4x/5 = 80
Or, x = (80*5)/4
Or, x = 100
So, total number of student = 100.
Ans: 100.
Total number of student = x.
Given as,
8 years age = 48
8 years above age = 48 *(2/3)
= 32.
Below 8 years age = x*20%
By condition,
X*20%+32+48 = x
Or, x*(20÷100) +80 = x
Or, x - x/5 =80
Or, (5x-x)/5 = 80
Or,4x/5 = 80
Or, x = (80*5)/4
Or, x = 100
So, total number of student = 100.
Ans: 100.
PADMAVATHI said:
3 months ago
GIVEN:-
20% of students [below 8yrs],
2/3 of no of students of 8yrs i.e 48 [above 8yrs]
Total no of "students" (x)= 100.
SOLUTION:
1) 20% of students (x).
=20/100 * 100 = 20 students.
2) 2/3 of students of 8yrs (48),
= 2/3 * 48 = 32 students.
3) = 20 + 32 + 48(already given) = 100 students[ANSWER].
20% of students [below 8yrs],
2/3 of no of students of 8yrs i.e 48 [above 8yrs]
Total no of "students" (x)= 100.
SOLUTION:
1) 20% of students (x).
=20/100 * 100 = 20 students.
2) 2/3 of students of 8yrs (48),
= 2/3 * 48 = 32 students.
3) = 20 + 32 + 48(already given) = 100 students[ANSWER].
(11)
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.
Narendra umraiya said:
1 decade ago
By 100% concept:
20% students is = remaining (exactly 8 yrs and above 8 yrs).
Below 8yrs i.e. 100%-20% = 80%.
80% = 48+2/3*48--equation 1 (48 is exactly 8 yrs and 2/3*48 is above 8 years a/c to question).
By equation 1 80% = 48+2/3*48 = 80.
100% = ? (100% means total students).
By cross multiply we get 100 answer.
20% students is = remaining (exactly 8 yrs and above 8 yrs).
Below 8yrs i.e. 100%-20% = 80%.
80% = 48+2/3*48--equation 1 (48 is exactly 8 yrs and 2/3*48 is above 8 years a/c to question).
By equation 1 80% = 48+2/3*48 = 80.
100% = ? (100% means total students).
By cross multiply we get 100 answer.
Soumyadeep Chatterjee said:
4 years ago
Let,
Total number of student = x.
Given as,
8 years age = 48
8 years above age = 48 *(2/3)
= 32.
Below 8 years age = x * 20%.
By condition,
X*20%+32+48 = x,
Or, x*(20÷100) +80 = x,
Or, x - x/5 =80,
Or, (5x-x)/5 = 80,
Or,4x/5 = 80,
Or, x = (80*5)/4,
Or, x = 100.
So, a total number of students = 100.
Ans: 100.
Total number of student = x.
Given as,
8 years age = 48
8 years above age = 48 *(2/3)
= 32.
Below 8 years age = x * 20%.
By condition,
X*20%+32+48 = x,
Or, x*(20÷100) +80 = x,
Or, x - x/5 =80,
Or, (5x-x)/5 = 80,
Or,4x/5 = 80,
Or, x = (80*5)/4,
Or, x = 100.
So, a total number of students = 100.
Ans: 100.
Sheshu said:
1 decade ago
Student below 8 years-------20%
So the rest 80% =(above 8 + exact 8)
Given above 8 =2/3 of students of exact 8 (i.e)48, so
Above 8==2/3*48
=32.
So total students will be 100%(20%+80%)
=20%+(above 8+ exact 8)
=20%+(32+48)
=20%+(80)
For 80%-------80
For 100%------?
Cross multiply 100*80/80==100.
So the rest 80% =(above 8 + exact 8)
Given above 8 =2/3 of students of exact 8 (i.e)48, so
Above 8==2/3*48
=32.
So total students will be 100%(20%+80%)
=20%+(above 8+ exact 8)
=20%+(32+48)
=20%+(80)
For 80%-------80
For 100%------?
Cross multiply 100*80/80==100.
Rahul ghosh said:
6 years ago
Let's total number of students is : x
Below 8 years :: 20 % x
=20/100 * X
= 20X/100.
Others students = X - 20X/100.
= 80X/100.
Absolute, 8 years students = 48.
Above 8 years students = 48 * 2/3.
= 32.
So,
80X/100 = 48 + 32,
X = 100 * 80/80.
= 100.
Below 8 years :: 20 % x
=20/100 * X
= 20X/100.
Others students = X - 20X/100.
= 80X/100.
Absolute, 8 years students = 48.
Above 8 years students = 48 * 2/3.
= 32.
So,
80X/100 = 48 + 32,
X = 100 * 80/80.
= 100.
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