The temperature is -4. At 7:00 am a warm front come through and the temperature increases 2 degrees every hour. At what time does the temperature reach 18 degrees?

at 6:00 pm the temperature reaches 18 degrees

Step-by-step explanation:

since the temperature increases linearly with the time then

t = t₀ + m * (T-T₀)  

where

t = time at temperature T

t₀= initial time at temperature T

m= increase in time with temperature

T₀ =  initial temperature

therefore replacing values

t = 7 hour + 1 hour/2°C* [18°C-(-4°C)]  = 18 hour → 18:00 = 6:00 pm

thus at 6:00 pm the temperature reaches 18 degrees