Answer :
Final answer:
Using unit conversion and proportion, it is calculated that a machine testing 32 units in 4 minutes will require 50 minutes to test a total of 400 units.
Explanation:
To determine how long it will take for a machine to test 400 units, when it can test 32 units in 4 minutes, we need to use unit conversion and proportion. First, we calculate the rate at which the machine tests units per minute:
Divide the number of units the machine can test by the time it takes to test them, which is 32 units / 4 minutes = 8 units per minute.
Then, we calculate the total time needed for 400 units by dividing the number of units by the rate,
which is 400 units / 8 units per minute = 50 minutes.
Therefore, it will take 50 minutes to test all 400 units.