1. Suppose you drive your car on a perfectly flat road at a constant speed with no wind. In this case, the amount of fuel, y, (in litre) needed is directly proportional to the distance travelled, x...

1. Suppose you drive your car on a perfectly flat road at a constant speed with no wind. In this
case, the amount of fuel, y, (in litre) needed is directly proportional to the distance travelled,
x (in kilometre).
(a) If the distance travelled increase, what can we say about the amount of fuel needed?
(b) If the relationship is given by y = 0.05x and x increase by 50 km, how much does y
increase?

(c) Now, suppose it takes 12 litre of fuel to travel 282 km. Find the constant of proportionality.
(d) In words, describe the meaning of this constant of proportionality.