Chapter 1.5, Problem 1CYU

To determine

To calculate :  The number of students who have earned each grade.

Answer to Problem 1CYU

Number of students of grade A=2

Number of students of grade B=6

Number of students of grade C=9

Number of students of grade D=3

Explanation of Solution

Given information: Total number of points= 450

A table showing number of points received by each student

Grade A is given if number of points $>=90\%$

Grade B is given if number of points $>=80\%\text{ and <=89\%}$

Grade C is given if number of points $>=70\%\text{ and <=79\%}$

And Grade D is given if number of points $>=60\%\text{ and <=69\%}$

Calculation:  According to the given information,

If number of points received by a student >= 405(which is $90\%of450$ ),

Then student is counted under Grade A,

Likewise, Number of points greater than and equals to 360(which is $80\%of450$ ) and less than 405, student is counted under Grade B.

Also, if Number of points varies between 315(which is $70\%of450$ ) and 359, then student is counted under Grade C.

Students having number of points greater than 270(which is $60\%of450$ ) and less than315 is counted under Grade D.

Therefore, according to given number of points in the question, number of students is calculated on the basis of above criteria.