In a class of 300 students, the number of boys is twice that of girls.

1.	In a class of 300 students, the number of boys is twice that of girls. If 50% of boysand 48% of girls appear in exams, how many students did not appear?
Answer» ANSWER: Total number of students absent = 152 GIVEN: In a class there are 300 students The number of boys is twice that of girls 50% of boys and 48% of girls appear in exams. TO FIND: How MANY students did not appear. EXPLANATION: Take number of boys as x and take number of girls as y. x + y = 300 Subsitute x = 2y in x + y = 300 2y + y = 300 3y = 300 y = 100 Subsitute y = 100 in x + y = 300 100 + x = 300 x = 200 Number of boys = 200 Number of girls = 100 Number of boys present = 50% Take the number of boys present as B $\dfrac{b}{200} \times 100 = 50 \% \\ \\ \\ \dfrac{b}{2} = 50 \\ \\ \\ b = 100$ Total number of boys present = 100 Total number of boys absent = 200 - b Total number of boys absent = 200 - 100 = 100 Number of girls present = 48% Take the number of girls present as g $\dfrac{g}{100} \times 100 = 48 \% \\ \\ \\ \dfrac{g}{48} =1\\ \\ \\ g = 48$ Total number of girls present = 48 Total number of girls absent = 100 - g Total number of girls absent = 100 - 48 = 52 Total number of students absent = 100 + 52 = 152 HENCE 152 STUDENTS OUT OF 300 WERE ABSENT FOR THE EXAM.

In a class of 300 students, the number of boys is twice that of girls. If 50% of boysand 48% of girls appear in exams, how many students did not appear?

Answer»

ANSWER:

Total number of students absent = 152

GIVEN:

In a class there are 300 students

The number of boys is twice that of girls

50% of boys and 48% of girls appear in exams.

TO FIND:

How MANY students did not appear.

EXPLANATION:

Take number of boys as x and take number of girls as y.

x + y = 300

Subsitute x = 2y in x + y = 300

2y + y = 300

3y = 300

y = 100

Subsitute y = 100 in x + y = 300

100 + x = 300

x = 200

Number of boys = 200

Number of girls = 100

Number of boys present = 50%

Take the number of boys present as B

$\dfrac{b}{200} \times 100 = 50 \% \\ \\ \\ \dfrac{b}{2} = 50 \\ \\ \\ b = 100$

Total number of boys present = 100

Total number of boys absent = 200 - b

Total number of boys absent = 200 - 100 = 100

Number of girls present = 48%

Take the number of girls present as g

$\dfrac{g}{100} \times 100 = 48 \% \\ \\ \\ \dfrac{g}{48} =1\\ \\ \\ g = 48$

Total number of girls present = 48

Total number of girls absent = 100 - g

Total number of girls absent = 100 - 48 = 52

Total number of students absent = 100 + 52 = 152