Raj earns 25 on an investment but loses 10 on another investment.if the ratio of the two investment is 3:5.what is the gain or loss on two investments taken together?

Consider the investment be x
then in first case:
investment=3x

s.p=3x*25/100
     =15x/4

in 2nd investment:
investment=5x

s.p=5x-10*5x/100
=9x/2

total s.p=15x/4+9x/2
=33x/4=8.25

profit%=8.25-8/8*100

profit%=3.125%