Lesson 14

Percent Error

View Student Lesson

Problem 1

A student estimated that it would take 3 hours to write a book report, but it actually took her 5 hours. What is the percent error for her estimate?

Solution

For access, consult one of our IM Certified Partners.

Problem 2

A radar gun measured the speed of a baseball at 103 miles per hour. If the baseball was actually going 102.8 miles per hour, what was the percent error in this measurement?

Solution

For access, consult one of our IM Certified Partners.

Problem 3

It took 48 minutes to drive downtown. An app estimated it would be less than that. If the error was 20%, what was the app’s estimate?

Solution

For access, consult one of our IM Certified Partners.

Problem 4

A farmer estimated that there were 25 gallons of water left in a tank. If this is an underestimate by 16%, how much water was actually in the tank?

Solution

For access, consult one of our IM Certified Partners.

Problem 5

For each story, write an equation that describes the relationship between the two quantities.

  1. Diego collected \(x\) kg of recycling. Lin collected \(\frac25\) more than that.
  2. Lin biked \(x\) km. Diego biked \(\frac{3}{10}\) less than that.
  3. Diego read for \(x\) minutes. Lin read \(\frac47\) of that.

Solution

For access, consult one of our IM Certified Partners.

(From Unit 4, Lesson 4.)

Problem 6

For each diagram, decide if \(y\) is an increase or a decrease of \(x\). Then determine the percentage.

Tape diagram A, 5 blue equal sections, all labeled x. 4 labeled y. Tape diagram B, 8 equal sections, all labeled y. 5 blue sections labeled x.

 

Solution

For access, consult one of our IM Certified Partners.

(From Unit 4, Lesson 12.)

Problem 7

Lin is making a window covering for a window that has the shape of a half circle on top of a square of side length 3 feet. How much fabric does she need?

Solution

For access, consult one of our IM Certified Partners.

(From Unit 3, Lesson 10.)