st andrews golf course in st andrews scotland is one of the oldest courses in the world. it is an 18-hole course that consists of par-3 holes, par-4 holes and par-5 holes. a golfer who shoots par at the old course at st andrews has a total of 72 strokes for the entire course. there are seven times as many par-4 holes as par- 5 holes,and the sum of the numbers of par-3 and par-5 holes is four.find the numbers of par-3, par-4 and par-5 holes in the course.

Answer 1

Let's set up some variables to keep track of the various items of interest.

a = # par-3 holes
b = # par-4 holes
c = # par-5 holes

We are told:
a+b+c=18 holes
b = 7c
a+c = 4
3a+4b+5c = 72 strokes needed to finish course

3(4-c) + 4(7c) + 5c = 72
12-3c + 28c + 5c = 72
30c = 60
c=2
b=14
a=2

And we didn't even need the fact that a+b+c=18, but it works out just fine.