Study the following information carefully and answers the questions given below.

There are 1500 students in a class. They studied four different subjects namely Maths, Physics, Chemistry and Biology. The ratio of number of Boys to girls is 8 : 7. 30% of the boys study Maths. Number of girls who studies Chemistry is 20%. Number of boys in Physics is 2 times of number of girls in Chemistry. Number of girls in Physics is (6)²% of total number of girls. Number of boys in Biology is half of number of girls in Physics. Total number of students in Biology is 207.

1) Find the difference between the number of girls in Maths to number of boys in Biology?

A.121

B.125

C.105

D.110

E.None of these

2) What is the ratio of the number of girls who studies Chemistry to number of boys who studies Maths?

A.1 : 4

B.7:12

C.5 : 7

D.6 : 13

E.None of these

3) Find the average number of students who studies in the subject of Chemistry and Maths.

A.350

B.366.5

C.372

D.380.5

E.None of these

4) Find the difference between the number of students who studies Physics to number of students who studies Chemistry

A.202

B.222

C.238

D.256

E.None of these

5) What is the percentage of girls in Biology to the total number of boys who studies Maths and Chemistry together?

A.20.55%

B.15%

C.18.75%

D.12%

E.None of these

Answers :

Explanation

Number of boys in the class is = 8/15 × 1500 = 800

Number of girls in the class is = 7/15 × 1500 = 700

Number of boys who studies Maths = 30/100 × 800 = 240

Number of girls who studies Chemistry is = 20/100 × 700 = 140

Number of boys in Physics is = 2 × 140 = 280

Number of girls in Physics is = (6)²% of 700 = 36/100 × 700 = 252

Number of boys in Biology is = 1/2 × Number of girls in Physics = 1/2 × 252 = 126

Total number of students in Biology is = 207

So, number of girls in Biology is = 207 – 126 = 81

Number of boys in Chemistry is = 800 – (240 + 280 + 126)

= 800 – 646 = 154.

Number of girls in Maths is = 700 – (252 + 140 + 81)

= 700 – 473 = 227

1) Answer: E

For question 21:

Number of girls in Maths is = 700 – (252 + 140 + 81)

= 700 – 473 = 227.

Number of boys in Biology is = 1/2 × Number of girls in Physics = 1/2 × 252 = 126

So, the required difference is = 227 – 126 = 101.

2) Answer: B

Number of girls who studies Chemistry is = 20/100 × 700 = 140

Number of boys in Maths = 240

So, the required ratio is = 140 : 240 = 7 : 12

Hence, the required answer is = 7 : 12

3) Answer: D

Number of girls who studies Chemistry is = 20/100 × 700 = 140

Number of boys in Chemistry is = 800 – (240 + 280 + 126)

= 800 – 646 = 154.

Number of boys who studies Maths = 30/100 × 800 = 240

Number of girls in Maths is = 700 – (252 + 140 + 81)

= 700 – 473 = 227.

So, the total number of students is = (294+ 467) = 761/2 = 380.5

Hence, the required

answer is = 380.5

4) Answer: C

Number of boys in Physics is = 2 × 140 = 280

Number of girls in Physics is = (6)²% of 700 = 36/100 × 700 = 252

So, total number of students who studies Physics = 280 + 252 = 532

Number of girls who studies Chemistry is = 20/100 × 700 = 140

Number of boys in Chemistry is = 800 – (240 + 280 + 126)

= 800 – 646 = 154.

So, total number of students in Chemistry = 140 + 154 = 294

Hence, the required difference is = 532 – 294 = 238.

5) Answer: A

Total number of students in Biology is = 207

So, number of girls in Biology is = 207 – 126 = 81

Number of boys who studies Maths = 30/100 × 800 = 240

Number of boys in Chemistry is = 800 – (240 + 280 + 126)

= 800 – 646 = 154.

So, total number of boys together = 240 + 154 = 394

So, the required percentage is = 81/394 × 100 = 20.55%