Question

The temperture in the rink must stay below 50 degrees Fahrenheit.. This morning the temperature was 71 degrees Fahrenheit. The ice rink runs a cooling device, that can decrease the temperature by 3.5 degrees every hour. How many hours will it take for the temperature to fall below 50 degrees ?

Answer 1

Answer:

it will take 6 hours to fall to 50 degrees, but it will take 7 hours to fall below 50 degrees.

Step-by-step explanation:

take 71 on your calculator and just subtract 3.5 until you get to 50 or below.

Answer 2

Answer:

The temperature needs to decrease 71° - 50° = 21° that at least not greater than 50°F

As we know, the device decrease the temperature down 3.5° every hour, so

21 : 3.5 = 6 hour

Call x is the hours we need to wait to let the device decrease, we have

x > 6