For the following questions answer them individually
P and Q jog along a circular track of 400 m in opposite directions from the same starting point starting together, with speeds 10 m/s and 40 m/s. Whenever they meet, P's speed is doubled and Q's speed is halved. After what time from start, will they meet for the third time?
Find the least number which when doubled will be exactly divisible by 12, 16, 18, 21 and 28.
If the length of a wire is doubled by taking more of wire, what happens to its resistance?
A cistern can be filled in 9 hours. But due to a leak, it takes one hour more. If the cistern is full,in what time will it become empty due to the leak?
Two articles cost Rs.2500 each. One is sold at 5% profit. On the whole if there is 20% profit,what is the percentage profit on selling the other article?