A sells an article to B at gain of 25% B sells it to C at a gain of 20% and C sells it to D at a gain 10%. If D pays Tk. 330 for it, how much did it cost to A?

Question: A sells an article to B at gain of 25% B sells it to C at a gain of 20% and C sells it to D at a gain 10%. If D pays Tk. 330 for it, how much did it cost to A?

Solution:
Let,
Cost Price for A was = 100

Then, CP for B = (100 + 25% of 100) = 125
CP for C = (125 + 20% of 125) = 150
CP for D = (150 + 10% of 150 ) = 165

But, D pay Tk. 660. Then it must be equal to,
165 = 330
1 = 330/165
∴ 100 = {330 × (100/165)} = 200

So, CP for A = Tk. 200