Explanation:
I suppose those are fractions.....
columbia = 4 3/5 carleton <=== columbia /(4 3/5 ) = carleton
carleton = 5 3/4 edward <=== sub in the value of carleton (above)
columbia / ( 4 3/5) = 5 3/4 edward multiply both sides by 4 3/5
columbia = 4 3/5 * 5 3/4 edward
= 23/5 * 23/4 edward = 26 9/20 edward (simplified)
( as an aside, I looked up Prince Edward Island high point = 499 ft
so Mount Columbia = 26 9/20 ( 499) = ~13 199 ft above sea level)