If the time increases by 5 years, then simple interest increases by Rs 3000 on a sum of Rs 5000. What is the rate (in percentage) of interest per annum?
In a farm, in addition to 48 hens there are 42 sheep and 11 oxen with some shepherds. If the total number of feet be 224 more than the number of heads, find the number of shepherd.
The potential difference between the terminals of an electric heater is 60 V when it draws a current of 4 A from the source. What current will the heater draw if the potential difference is increased to 127.5 V ?