David C. answered • 02/14/18

Tutor

4.9
(78)
ACT, SAT, Testing Skills, Algebra, Calc, Chemistry, Physics,

**x+y=50**

**20x+30y=1300**

**Substitute**

**y=50-x (1st equation) into 2nd equation to get**

**20x +30(50-x)=1300**

**20x +1500-30x=1300**

**x=-200/-10=20**

**Answer x=20 gallons**

**x+y=50**

**20+y=50**

**y=30 gallons**

**check your answer**

**20x +30y = 1300**

**20(20) + 30(30)= 1300**

**400+900=1300 checks out correct**