1. A tap can fill a drum in 60 minutes. When it has been open for 20 minutes, a hole is made in the bottom of the drum to siphon the water Into a sump. The drum is filed after a further 120 minutes. In how many minutes can the hole alone can empty the complete contents of the drum into the sump?
2. A series of discounts of 20%, 10% and 10% is equivalent to a single discount of
3. Five years ago, the sum of Alwyn’s age and his father’s age was a third of five times the average of present ages of Alwyn and his father. If Alwyn will be 15 years old in 5 years from now, how old is Alwyn’s father now?
d. None of the options
4. If 7x-21y = 20, then how many positive integer solutions does the equation have?
5. If you have 150 pebbles and need to make packets out of it in such a way that if any number of pebbles up to 150 is required you can hand it over without opening the packets, what is the minimum number of packets you need?
d. None of the given options