Question

Tommy is measuring his bedroom to determine how much paint he needs to cover the walls.

One wall is 15 feet long, but Tommy records the length as 13.5 feet.
What is the percent error in Tommy's measurement?
1.596
1096
11.196
9096

Answer 1

Tommy's percent error is 10%.

Explanation:

Percent error is found with the formula
`\displaystyle P=\big(V_A-V_E)/(V_E)\big|*100\%`, where P is the percent error,
`V_A` is the actual value that you measure, and
`V_E` is the accepted value or the expected value. For instance, the accepted value for specific heat of water is:

`\bullet \ 4.184\ \text{joule/gram degrees Celsius}`

This would also be the expected value in a lab experiment.

We are given the accepted value of 15 feet. Therefore, we know that this is
`V_E.` Then, we see that Tommy measures the length as 13.5 feet - this is
`V_A.`

Finally, we need to place these values into the equation and solve for P.

`\displaystyle P = \big(V_A-V_E)/(V_E)\big*100\%\\\\P = \big(13.5-15)/(15)\big*100\%\\\\P = \big-(1.5)/(15)\big*100\%\\\\P = \big-(1)/(10)\big*100\%\\\\P = \big-0.1\big*100\%\\\\P = \big-10\%\big\\\\P = |-10\%| = 10\%`

Therefore, Tommy's percent error is 10%.