Test Preparation on Mathematics Olympiad Class-5 Test Prep-5

Sam bought a book for Rs.428 and sold it sold it at a loss of Rs.68. What was the SP?

CP = Rs.100, SP = Rs.130, Overhead charges = Rs.20, then ,
Find the gain or loss, 

A dozen pens were bought for Rs.120 and sold for Rs.15 each. Therefore
the profit on each pen and the profit on all the pens is______,________
respectively.

Excess amount in the Selling price as compared to the Cost price is
called________

CP = Rs.6oo, Profit percentage = 15% , then the profit is______