Justin's doctor said that the expression x+y+5/2, where x and y are his parents' current heights in inches, gives an estimate of how tall Justin will be as an adult. Justin's work evaluating the formula is shown below.

Mom's height = 54 inches

Dad's height = 71 inches

71+54+5/2 = 71+27+5=130 inches

What error did Justin make?

He should have made x equal 54 and y equal 71.

He should have added the values in the numerator before dividing by 2.

He should have divided the 71 by 2 instead of the 27.

He should have made the numerator 76 + 59.

Question

Mathematics

Aubrey Fletcher

23 November, 00:38

Justin's doctor said that the expression x+y+5/2, where x and y are his parents' current heights in inches, gives an estimate of how tall Justin will be as an adult. Justin's work evaluating the formula is shown below.

Mom's height = 54 inches

Dad's height = 71 inches

71+54+5/2 = 71+27+5=130 inches

What error did Justin make?

He should have made x equal 54 and y equal 71.

He should have added the values in the numerator before dividing by 2.

He should have divided the 71 by 2 instead of the 27.

He should have made the numerator 76 + 59.

+3

Answers (2)

Know the Answer?

Aidan Ponce · Answer 1

Sorry to say, but I think they are all wrong. Without brackets technically only the 5 is divided by 2. I think it means (71 + 54 + 5) / 2 (Mom is a little on the short side. 4 feet 6 inches to be exact.)

So I guess the correct answer is add the numerators and divide by 2

71 + 54 + 5 = 130

Now divide by 2

130 / 2 = 65.

I'm not at all sure this is correct. Brackets make life a whole bunch easier.

Jensen Mckee · Answer 2

The correct answer is b) he should have added the values in the numerator before dividing by 2