Deepinder lent Rs 8200 to Jairaj for 16 years and Rs 4900 to Karna for 15 years on simple interest at the same rate of interest and received Rs 19446.5 in all from both of them as interest. The rate of interest per annum is:
Alarms from 3 different clocks sound after every 2, 4 and 6 hours, respectively. If the clocks are startedat the same 6 time, how many times do the alarms ring together in 3 days?