For the following questions answer them individually
The cost price of 18 articles is equal to the selling price of 15 articles. The gain percent is--
12 copies of a book were sold for Rs. 1800, thereby gaining the cost price of 3 copies. The cost price of a copy is-
A sum of money was invested at a certain rate for 2 years. Had it been invested at 3% higher rate of interest, it would have fetched Rs. 450 more. The sum invested was---
A sum of money put out at C.I. amounts to Rs. 16,900 in 2 years and to Rs. 17,576 in 3 years. Find the rate p.a.---
On what sum of money will the compound interest for 3 years at 5% per annum amount to Rs. 630.50 ?
A sum of Rs. 625 is made up of 80 currency notes which are either Rs. 10 or Rs. 5 denomination. The number of Rs. 10 notes are---------