H linearly related to T, w/ (T,H) = (10, 2480); +15 on T means -40 on H; find eqn.

[21cunninghama]

Please help! I do not know how to answer this word problem on linear equations:

The amount of heat H (in joules) required to convert one gram of water into vapor is linearly related to the temperature T (in °C) of the atmosphere. At 10°C this conversion requires 2480 joules, and each increase in temperature of 15°C lowers the amount of heat needed by 40 joules. Express H in terms of T. Your answer must be exact.

 

[Deleted member 4993]

The amount of heat H (in joules) required to convert one gram of water into vapor is linearly related to the temperature T (in °C) of the atmosphere. At 10°C this conversion requires 2480 joules, and each increase in temperature of 15°C lowers the amount of heat needed by 40 joules. Express H in terms of T. Your answer must be exact.

If you plot H(Joules) as dependant variable and T (^oC) as independent variable - you should get a straight line (linear relationship).

From the statement of the problem:

each increase in temperature of 15°C lowers the amount of heat needed by 40 joules.

What would be the slope of that line?