Question

A speedometer has a percent error of 10%. The actual speed of the car is 40 mph.

Select from the drop-down menus to correctly complete the statement.

The speedometer is likely to show the speed is either
Choose...
mph or
Choose...
mp

Answer 1

Given that the speedometer has a percent error of 10% and the actual speed of the car is 40 mph, we can calculate the possible readings on the speedometer.

1. Calculate 10% of the actual speed:
\[
10\% \text{ of } 40 \text{ mph} = 0.10 \times 40 = 4 \text{ mph}
\]

2. Determine the range of possible speeds:
- The speedometer could show a speed that is 10% higher than the actual speed:
\[
40 \text{ mph} + 4 \text{ mph} = 44 \text{ mph}
\]
- It could also show a speed that is 10% lower than the actual speed:
\[
40 \text{ mph} - 4 \text{ mph} = 36 \text{ mph}
\]

Thus, the speedometer is likely to show the speed is either **36 mph** or **44 mph**.

So the completed statement is:

The speedometer is likely to show the speed is either **36** mph or **44** mph.