Let number of boys = B

Number of girls = G

From the given data,

1B/3 + 1G/2 = 300

But given B/3 = 100

=> B = 300

G/2 = 300 - 100

G = 200 x 2

=> G = 400

Therefore, total number of students in the college = B + G = 700.

Let marks obtained by S = M

R's marks = 0.80M

Q's marks = 1.25 (0.80M)

P's marks = (0.90) (1.25) (0.80M)

= 0.9M

But 0.9M = 360

M = ?

M = 400

Hence % of marks obtained by S

= 400/500 x 100 = 80%.

Let number of pages in a book = p

According to questions

p - [3p/7 + (2/5 x 4p/7)] = 36

= p - 23p/35 = 36

=> 12p = 36 × 35

p = 105

Let C's salary be Rs. x

Then B's salary = 80x/100

=> A's salary = (50/100) * (80x/100) = 40x/100

But given total earnings in a month = 22000

=> x + 80x/100 + 40x/100 = 22000

=> x + 120x/100 = 22000

=> x = 10000

=> A's salary = 40 x 10000/100 = Rs. 4000 

only (c) is correct since it is divisible by 4.

Let the original number of element  be x then the new no.of elements will be 

            4 x 5 = K                               

So K must be divisible by 4

Since,      x =  Kx5/4

The surface area of a cube = 6 a 2 =  6 s i d e 2

New  Surface area = 6 x 1.44 a 2

Therefore, 0 . 44 a 2 a 2 x 100 = 44%

Let N be the required number. 

=>  60 100 x 2 7 x 3 4 x N = 2664  

=> N = 2664x2x7x5/9  

=> N = 20720.

In the question it is asked for 5% of 1500

5 x 1500/100 = 15 x 5 = 75.

Hence, 5% of 1,500 is equal to 75.

From the given data,

20% of K = 32% of N

V = 4/5 N

Given Vipin's salary = 3.84 lpa = 3.84/12 = 32,000 per month

Now, N = 5/4 x 32000 = 40000

Now K = 32/20 x 40000 = 64000

Hence, karthik's monthly salary = Rs. 64000.

Required % is given by 

=>  12 100 - 12 x 100

= 1200/88

= 13.636%