Neal went canoeing on the Spartan River last Saturday. He traveled 15 miles downstream with the current and then turned around and traveled the same 15 miles upstream against the current. The trip took him a total of 4 hours. If Neal paddled his canoe 8 miles per hour in still water, which equation could be used to determine the speed of the current in the river, x?

In a coastal town, the humidity, measured in grams of water per kilogram of air, increases by 43% for every 1 degree celsius increase in temperature. a scientist observes that the humidity on monday morning is 5.75 grams per kilogram. he wants to know how much the temperature must increase for the humidity to reach at least 49.17 grams per kilogram. let t represent the increase in temperature, in degrees celsius, from monday morning's observation. write an inequality to represent the situation, and use it to determine the desired temperature increase.