Manan buys 9 pens for Rs.36 and sells them at the rate of 12 pens for Rs.52. Find the gain or loss percent.
Ram buys 40 pencils for Rs 70 and sells them at the rate of 30 pencils for Rs 80. Find gain or loss percent.
A boy buys 9 apples for Rs.9.60 and sells them at 11 for Rs.12. Find his gain or loss percent.