A sum fetched a total simple interest of Rs 1200 at the rate of 7.5%/yr in 4 years. What is the sum (in Rs)?

If a boat goes a certain distance at 30 km/h and comes back the same distance at 20 km/hr, what is the average speed (in km/hr) for the total journey?

When a number is increased by 24, it becomes 104% of itself. What is the number?

A wholesaler sells a jacket to a retailer at a profit of 25% and the retailer sells it to a customer at a profit of 20%. If the customer pays Rs. 2,400, what had it cost (in Rs) the wholesaler?

The average marks of 10 students in an examination was 25. It was later found that the marks of one student had been wrongly entered as 34 instead of 43. What is the correct average?

The ratio of present ages of R and S is 6:7. Before 12 years the ratio of their ages was 9:11. What is R's present age (in years)?

If 1 saree is offered free on purchase of 3 sarees, what is the effective discount on each saree?

What is the area (in sq cm) of a regular hexagon of side 6 cm?