For every mile of highway on land, the city needs two truckloads of asphalt and one gallon of paint. For every mile of highway on bridges, the city needs one truckload of asphalt and three gallons of paint. The city has 50 truckloads of asphalt and 80 gallons of paint.
(a) What is the largest total number of miles of highway the city can build?
(b) Suppose the city is on an island and must build at least 25 miles of highway on bridges to reach other islands. Now what is the largest total number of miles of higway the city can build?
A Are they are limited to the amount of paint they have? 80g / 1 g/mile = 80 miles using all of the paint
50 trucks /2 trucks/mile = 25 miles using all of the trucks of asphalt
B 25 miles of bridge = = 25 trucks leaving 25 trucks of asphalt 25 trucks/2 trucks/mile = 12.5 miles of land highway possible
25 miles of bridge = 25 miles x 3 gal/mile = 75 gallons of paint leaving only 5 gallons of paint for 5 add'l land miles
25 miles of bridge + 5 land miles = 30 miles total highway .