Question

a group of 400 students took certain examination.60% of boys 80% of girls had cleared the cutt off in the examination. if the total % of students qualifying is 65%, then how many girls appeared in the exam?
A) 100  B)150   C)200  D)250   E)300

Answer 1

Let Boys be x, and girls be y.
So total , x+y=400

60x/100 boys cleared and 80y/100 girls.

now  {( 0.6x +0.8y)/400 }*100= 65

0.15x +0.2y =85

So 
x=300
and y=100(girls)

Answer 2

Answer:

Concept:

The term percentage is used to measure the proportion of value in terms of the original value. Percentages are widely used in business to calculate the percentage of profit or loss of a business. It is also used in schools and colleges to represent grades obtained by students. Students' grades can be estimated using a percentage formula. A percentage generally defined as the ratio of any value to the total value multiplied by 100. The symbol used to express a percentage is %.

Find:

We have find the how many girls appeared in the exam

Given

a group of 400 students took certain examination.60% of boys 80% of girls had cleared the cutt off in the examination

Step-by-step explanation:

The correct option is C 100

The ratio of boys and girls appearing for the exam can be seen to be 3: 1

This means that out of 400 students, there must have been 100 girls who appeared in the exam.

Let the number of boys be 'x'.

Then,

0.6x + 0.8(400-x) = 0.65(400)

x = 300

Hence, number of girl students appeared in the exam = 400-300 = 100.

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