Two triangles ABC and DEF are similar. The smallest side of ABC is equal to 15 units. If the sides of ABC are in the ratio 3 ∶ 4∶ 5, and the area of DEF is half of the area of ABC, then what is the largest side of DEF (in units)?
A sells an object to B at 10% profit. B sells it to C at 60% profit C sells it to D at 12½% profit. If D paid ₹59.40 , then at what price did A buy it?