Answer: the graph increases from left to right, since the price goes up. If you were to actually graph this, the years would be on the bottom and the price would be on the left side, so since the price is going up, so is the graph. :)
angle EPF = angle DPG
=> 4x + 48deg = 7x
=> 3x = 48 deg
=> x = 16
=> angle EPF = 4(16) +48 = 112deg
In what I know of this problem and what you told me I think there is a 1/2 chance!
think about it, if the life span is 15 years old with standard deviation of 3 then that means we can have bats from 12~18 years old and the mean of the 50 numbers can be anything between that depending on the results we got. Then half of values in interval 12~18 is over 15 which gives it a 1/2 probability!