A car is driving down a road at a normal speed of 50 miles per hour. It enters a hilly area of gradual incline and decline, where it must drive 50 miles up hill and then 50 miles downhill. If this 100 mile section of road takes 2.6 hours to traverse instead of the expected 2 hours (the time it would take if the road was completely flat) determine the speed that the hills add or subtract when going over.

Acoffee shop orders at most $3,500 worth of coffee and tea. the shop needs to make a profit of at least $1,900 on the order. the possible combinations of coffee and tea for this order are given by this system of inequalities, where c = pounds of coffee and t = pounds of tea: 6c + 13t ≤ 3,500 3.50c + 4t ≥ 1,900 which graph's shaded region represents the possible combinations of coffee and tea for this order?