The outdoor temperature was 18 degree at midnight. The temperature declined 7 degree each hour for the next 4 hours. What was the temperature at 4 a.m?
midnight is 12
12 to 1 is 1 hour
1 to 2 is 2
2 to 3 is 3
3 tof 4 is 4 hour
4 hour total
amount declined=number of hours times amount decilie per hour
amount decline=4 times 7=28
18 decline 28
18-28=-10
end temp at 4am=-10 degrees