Quantitative Aptitude - Arithmetic Ability Questions

The ratio of present ages of R and S is 11:17. Before 11 years the ratio of their ages was 11:20. What is R's present age (in years)?

By selling 90 pens for Rs 80 a man loses 20%. What should be the selling price (in Rs) of 90 pens for 20% profit?

A sum becomes Rs 2286 in 3 years and Rs 2448 in 4 years at simple interest. What is the rate (in percentage) of interest per annum?

A man buys a watch for Rs1950 in cash and sells it for Rs 2200 at a credit of 1 yr. The rate of interest is 10% per annum. Then he gains or loose how much amount?

5% of a = b, then b% of 20 is the same as __________.

Two typists of varying skills can do a typing jobin6 minutesifthey work together.Ifthe first typist typed alone for 4 minutes and then the second typist typed alone for 6 minutes, they would be left with 1/5 of the whole work.Howmany minutes would it take the slower typist to complete the typing job working alone?

Cost of 8 pencils, 5 pens and 3 erasers is Rs 111. Cost of 9 pencils, 6 pens and 5 erasers is Rs 130. Cost of 16 pencils, 11 pens and 3 erasers is Rs 221. What is the cost (in Rs) of 39 pencils, 26 pens and 13 erasers?

21% of 500 + 31% of 1100 - 30% of 790 = ?