Quantitative Aptitude - Arithmetic Ability Questions

Two pipes, when working one at a time, can fill a cistern in 3 hhrs and 4 hrs, resp while a third pipe can drain the cistern empty in 8 hrs. All the three pipes were opened together when the cistern was 1/12 full. How long did it take for the cistern to be completely full?

Which instrument is used for viewing the sun?

The marked price of an article is 60% more than its cost price. What maximum discount percentage can be offered by the shopkeeper to sell his article at no profit or no loss?

If (x + 1/x) = 3, then x8+1x8 is equal to

1/4 of 12?

45 men or 60 boys can do a piece of work in 20 days. How many days will 15 men and 20 boys take to complete the work?

Dhruv's birthday is on Sunday 28th May. On what day of the week will be Sahil's Birthday in the same year if Sahil was born on 19th October?

The ratio of ages of the father and mother was 11:10 when their son was born. The ratio of ages of the father and mother will be 19:18 when the son will be twice his present age. What is the ratio of present ages of father and mother?