Problem: An engineer said he could finish a highway section in days with his present supply of a certain type of machine. However, with more of these machines the jab could be done in days. If the machines all work at the same rate, how many days would it take to do the job with one machine?
Answer Choices:
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B.
C.
D.
E.
Solution:
In day, machines can do of the job and machines of the job. machines can do of the job in day, and machine can do of the job in day. Hence, days are needed for machine to complete the job;
or
, that is, machines can do of the job in day, etc.