Product of digits of a 2-digit number is 18. If we add 63 to the number, the new number obtained is a number formed by interchange of the digits. Find the number.
A boat goes 15 km upstream and 10 1/2 km down stream in 3 hrs 15 min. It goes 12 km upstream and 14 km downstream in 3 hrs. What is the speed of the boat in still water?
Among four bags, average weight of last three bags is 18 kg and the average weight of first three bags is 19 kg. If the weight of last bag is 22 kg, then what is the weight (in kg) of first bag?