A carpenter makes 3 beds every day. A military school needs to organize beds for 143 soldiers. If there are 5 carpenters working on the job, how many whole days in advance should they receive the order and start working in order to finish the right number of beds assuming that each bed is used by two soldiers?
A)3.
B)4.
C)5.
D)6.
E)7.
143 soldiers is not divisible by 2 so we need at least 72 beds (one will sleep alone).
The carpenters together can complete 15 beds a day.
72/15 is between 4 and 5 so they will need 5 days notice in order to complete the job on time.
The best answer is C.