Question

The label on the car's antifreeze container claims to protect the car between −40°C and 125°C. To convert Celsius temperature to Fahrenheit temperature, the formula is C = (F − 32). Write and solve the inequality to determine the Fahrenheit temperature range at which this antifreeze protects the car.

Answer 1

The condition 'temperature between -40°C and 125°C' can be written as inequality -40°C ∠ x°C < 125°C

Formula of changing degree Celcius to degree to degree Fahrenheit is given
°C = 5/9 (°F - 32)
Rearranging to make °F the subject

°F =
`(9)/(5)C+32`

Substitute °C = -40
°F =
`(9)/(5)(-40)+32 = -40`

Substitute °C = 125
°F =
`(9)/(5)(125)+32 = 257`

Substitute °F = -40 and °F = 257 into the inequality

-40°C < x°C < 125°C
-40°F < F < 257°F

Correct answer: B