Question

In an examination, a student''s average marks were 63. If he had obtained 20 more marks for his geography and 2 more marks for his history, his average would have been 65. How many subjects were there in the examination?.Find the answer

Answer 1

Answer:

11

As we know that two subjects are geography and history.

So let other subjects are = x

and total marks = y

A.T.Q,

y/2+x =63 (average = total marks / total subjects )

y = 63(2+x)

y = 126 + 63x. -(1)

Now total marks are = y+22 (20+2)

and average = 65

A.T.Q,

y+22/2+x =65

y+22 = 65(2+x)

y+22 =130+65x. -(2)

Putting equal equation (1) and (2),we get

130+65x=y+22

126+63x=y

4+2x=22

2x=18

x=9