<em>a</em> = 8 - a train arrives at the station once every 8 minutes, so for any given 8 minute interval, a randomly selected train has uniform probability of arriving at the station at some point in this time.
<em>f(x)</em> = 1/8 - the area under the graph of <em>f(x)</em> must be equal to 1. This area corresponds to a rectangle with length <em>a</em> = 8 and height <em>x</em> such that 8<em>x</em> = 1. Solving for <em>x</em> gives 1/8.
<em>P</em> = 5/8 - this is equal to the area under the graph over the interval [0, 5], which is the area of a rectangle with length 5 and height 1/8.
When sides are doubled, the area of new triangle will always be 4 times the original, the change in area will be 3 times. Hence the % change will always be 300% irrespective of the type of triangle.
