book Maths Puzzle Numerical Ability

If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2 days, how long would the job take if they worked together to complete it?

Read Solution (Total 0)

book Other Question

A computer is infected with the Boro virus. Assume that it infects 20 other computers within 5 minutes; and that these PCs and servers each infect 20 more machines within another five minutes, etc. How long until 100 million computers are infected How do I simplify and divide teh square root of 7 over the square root of 8?