1]A man bought a number of clips at 3 for a rupee and an equal number at 2 for a rupee.At what price per dozen should he sell them to make a profit of 20%
a]12 b]6 c]10 d] 2

Lets assume a dozen of clips were brought at 3 for a rupee and another dozen of clips were brought at 2 for a rupee
total CP for 1 dozen in which the cost is 3 for a rupee= 12/3 =4
total CP for 1 dozen in which the cost is 2 for a rupee= 12/2 = 6

total cp for 2 dozens = 6+4 = 10
percentage profit = 20% on Rs. 10 = 20/100 * 10 = Rs.2
After percentage profit the SP of 2 dozen is
Profit = SP - CP
SP = Profit + CP
SP = 2+ 10 = 12
SP of 1 dozen = 12/2 = 6