Rock climbing routes are rated on a scale of difficulty with the higher the number
the more difficult the route. Sally tried several shoe sizes on each of several routes of varying
difficulty and found that when she wore smaller shoes, she could climb routes of greater
difficulty. If D represents the difficulty rating of a rock climbing route Sally could climb, and s
represents the size of the shoes Sally wore on such a route, then which of the following could
express D as a function of s?

a) D(s) = s^2
b)D(s)= square root s
c)D(s)=4s
d)D(s)=s-3.5
d)D(s)=4s/s

Question

Rock climbing routes are rated on a scale of difficulty with the higher the number 
the more difficult the route.  Sally tried several shoe sizes on each of several routes of varying 
difficulty and found that when she wore smaller shoes, she could climb routes of greater 
difficulty.  If D represents the difficulty rating of a rock climbing route Sally could climb, and s
represents the size of the shoes Sally wore on such a route, then which of the following could 
express D as a function of s?

a) D(s) = s^2
b)D(s)= square root s
c)D(s)=4s
d)D(s)=s-3.5
d)D(s)=4s/s