Machines, parts and hours — proportion in two directions
A two-step proportion problem linking machines, parts and hours, solved by finding a single rate.
The Question
5 machines make 300 parts in 4 hours. How long would 8 machines take to make 960 parts, working at the same rate?
The Answer
Reveal the Answer
One machine makes 300 ÷ 5 ÷ 4 = 15 parts per hour. Eight machines make 120 per hour. 960 ÷ 120 = 8 hours. Insist on the per-machine-per-hour rate — it stops the double-proportion confusion.
Now watch the solution
Practice Sheet + Marked Answers
The four-question practice sheet, the solutions in our teaching voice and a self-marking quiz for this question are part of The Question Desk course — every school day of the term, with progress you can see. Enrolled group students get it included.
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