In a science experiment, the temperature of a substance is changed from 42 degrees to -54 degrees at an average rate of -12 degrees per hour. Over how many hours does the change take place?

There are a couple of ways to do this. The easiest is to take the number of degrees between 42 and - 54 and divide by 12.

Method

the number of degrees is abs(42) + abs(-54) = 42 + 54 = 96

Now divide by 12

Hours = 96 / 12 = 8 hours.

from the figure we get,

the x axis shows   the months and,

the y-axis shows the number of satisfied customer.

each line or each cell in upward direction (y-axis) shows 500.

the appropriate scale for the y - axis is: -

a = 2000 customers

b = 4000 customers

c = 6000 customers

d = 8000 customers

e = 10000 customers

f = 12000 customers

g = 14000 customers