[quote="lnaik"]In this problem basically asking if Carlos rate > 12 miles/hr
1. after calc rate >10.something
2 after calc rate <12> we will call this distance x so is x>31680?
S1: 16ft/s< is carlo's rate. well it could be 16.0000000000001ft/s or
20ft/s. Just try 16ft per/sec to get the idea where its at. We get 30min*60sec ---> 1800 sec. 1800*16=28800ft. So the real distance or x is going to be a lot greater or it could be just a little bit greater than 28800ft.
S2: 18ft/s > carlo's rate. Again use 18ft/s as a benchmark b/c it could be 17.999999999999999999999 or 1 ft/s.
18*1800= 32400. So it could be a little less than 32400 or a lot less than 32400. Insuff.
Essentially the faster carlo's goes the greater the distance.
now we can make an inequality for x. 28800<x<32400>31680. But we don't know anything else than the above info.
So E it is.