The method that will not give the correct number of inches is that the total length of the plant in a week is 19/4 inches.
Length of the small plant = 2 1/2 = 5/2 inches
Rate of growth = 3/4 inches
Increase in length in 3 weeks will be:
= 3 × 3/4 = 4
Total length = 5/2 + 9/4
= 19/4 inches.
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