A certain sum of money at simple interest amounts to Rs.1020 in 2(1/2) years and to Rs. 1067.20 in 4 years. The rate of interest per annum is:

In a sale, a perfume is available at a discount of 15% on the selling price. If the perfume’s discounted selling price is Rs.3675.40, what was the original selling price of the perfume?

In order to obtain an income of Rs. 600 from 10% stock at Rs 96,one must  make an investment  of