Calculus
posted by Cyndy .
On an 18hole golf course, there are par3 holes, par4 holes and par5 holes. A golfer shoots a par of 70 for the 18 holes. There are twice as many par4 holes as par5 holes. How many of each type of hole are there on the golf course?

number of par 5  x
number of par 4  2x
number of par 3  18x2x = 183x
solve
5x + 4(2x) + 3(183x) = 70
..
.
x = 4
par 5  4
par 4  8
par 3  6