Question

A tree is 2 1/2 feet tall. how tall will it be in 3 years if it grows 1/4 foot each year.

Which method will NOT give the correct number of feet

Answer Choices:

a. add 2 1/2 + 1/4 + 1/4 + 1/4
b. multiply 2 1/2 x 3 and then add 1/4
c. multiplu 3 x 1/4 and then add 2 1\2
d.multiply 3 x 1\4 and then add 2 1/2

Answer 1

The answer would be option B "multiply 2 1/2 x 3 and then add 1/4." If you multiply 2 1/2 by three your adding on to the answer. You would have to multiply 1/4 by three then add 2 1/2 to get your answer. It's not option A because your adding the three 1/4's together then multiply it by 2 1/2 which is one of the most common ways to solve this question. It's not option C because you are multiplying 1/4 by 3 which saves all the time adding 1/4 + 1/4 + 1/4. It's also not option D because the / are just in different directions which doesn't matter.

Hope this helps!