Aptitude - Percentage - Discussion

Let the total students be x.

20%of x = No of students below age 8.

48 = No of students of age exact 8. Given.

No of students above age 8 is 2/3 of no of students of age exact 8.

That is 2/3 of 48 = 32.

So above 8 is 32.

Exact 8 is 48x. Total of above is 80.

Now students below age 8 is 20% of total.

Therefore 20/100 of x = (x-80).

20x = 100x-8000.
8000 = 80x.
x = 100.

Therefore answer is 100.

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.

No of students of age 8 is 48.

Given no of students above 8 = 2/3 of 48 = 32.

20 % are below 8 age.

Therefore 80 % are equal or above 8.

Therefore 80 % of x = 80 (32 + 42).

So x = 100.

Why 2/3?

Please clear that how come answer?

FOR You @ANKIT.

LET total no.of students = x.
According to question below 8 years = 20% of x, i.e = 20x/100.

Again acc. to question no.of exact years = 48 and no.of above 8 years = two third of number. exact 8 year i.e = 2/3 of 48 = 32.

Now no.of exact 8 years = 48, above 8 years = 32 and below 8 years = 20x/100.

So total no.of students = 48+32+20x/100 = x(that we have taken at beginning),

So now 80+20x/100 = x,
20x/100 = x-80,
20x = 100x-8000,
100x-20x = 8000,
80x = 8000,
x = 8000/80 = 100(i.e total no.of students) ANS.

I THINK YOU UNDERSTAND..THANK YOU.

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.

Thanks @Vinod Anand.

I understand your explanation.

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.

I like your method @Showry.