An oil company wants to mix two grades of rocket fuel costing $3 and $4 per gallon,respectively with purified ethanol costing $8 per gallon to obtain 140 gallons of hybrid fuel costing NASA $6 per gallon. If the oil company also wants the amount of lower grade fuel to be twice that of higher-grade rocket fuel,how many gallons of each variety of fueling product should be mixed? USE A 3 - BY- 4 MATRIX TO SOLVE THE PROBLEM