2/5 divides by 4/1 = 1/10
X=1/10
2.4<7
2.4 / 0.6 = 4
2.4 / 2.4 = 1
4.8<7
4.8 / 0.6 = 8
4.8 / 2.4 = 2
The product of 3p and q-3 would be put in to equation form like this: 3p(q-3)
To find your answer. You have to distribute the 3p to by individually multiplying it by q and -3
It should now look like this:

So your answer is:
Let the total no. of 25 p coins be x
50p coins = 2x
Value of 25 p coins ( in rupees) = 0.25*x =0.25x
Value of 50p coins ( in rupees) = 0.5*2x = x
0.25x+x = 25
1.25x =25
x = 25/1.25 = 20
no. if 25p coins = 20
and 50p coins = 2*20 = 40
It would be 10 bc ten is the next number i guess