A condominium building has 25 condo units. Each unit has 5 windows. Ryder said that there are 125 windows altogether.

Which estimate can be used to see if Ryder’s answer is reasonable? Is Ryder correct?

A.
30 × 5
The answer is not reasonable. Ryder is not correct.

B.
30 × 5
The answer is reasonable. Ryder is correct.

C.
30 ÷ 5.
The answer is not reasonable. Ryder is not correct.

D.
30 + 5.
The answer is reasonable. Ryder is correct.

Q&A Education