5 . A's capital exceeds B's capital by $41 \over 100$ of B's capital. B invests his capital at compound interest for 3 years at 5% per annum. At what rate per cent per annum at simple interest must A invest his capital in order that at the end of 3 years, the two amount may be the same.
6 . The bacteria in a culture grows by 5% in the first hour, get destroyed by 5% in the second hour and again grows by 5% in the third hour. If the count of the bacteria at the end of the third hour is 8.3794 x $10^8$, find the original count of bacteria in the sample
7 . A person takes a boat from place A to place B and returns to A. Place A and B are 21 km apart and he takes 10 hours to go and return. The time taken by the boat to row 7 km downstream is equal to the time taken by the boat to row 3 km upstream, then what is the speed of the current?
8 . A trader sells two articles, one at a loss of 10% and another at a profit of 15%,but finally there is no loss or gain. If the total selling price of these two articles is ' 12,000. Find the difference between their cost prices
9 . When a train starts, there are 240 passengers. At the first station 12 passengers got down and 22 passengers got into the train. At the second station 20% of the passengers got down and at the third station 32 passengers get into the train and some passenger get down and now finally there are 85% passengers in the train. Find the number of passenger who got down at the third station.