On an 18-hole golf course, there are par-3 holes, par-4 holes and par-5 holes. A golfer shoots a par of 70 for the 18 holes. There are twice as many par-4 holes as par-5 holes. How many of each type of hole are there on the golf course?

Answer 1

number of par 5 ---- x
number of par 4 ---- 2x
number of par 3 ---- 18-x-2x = 18-3x

solve
5x + 4(2x) + 3(18-3x) = 70
..
.
x = 4

par 5 --- 4
par 4 --- 8
par 3 --- 6