Three apples and 2 oranges cost $0.65. Two apples and 5 oranges cost $0.80. What is the cost of 1
apple and 1 orange?

Let a = apple and o = orange.

Solve: { 3a + 2o = 0.65
{ 2a + 5o = 0.8

2(3a + 2o = 0.65) = 6a + 4o = 1.3
- 3(2a + 5o = 0.8) = - (6a + 15o = 2.4)

-11o = -1.1; o = 0.1
Solve for a: 3a + 2(0.1) = 0.65; 3a + 0.2 = 0.65
3a = 0.45; a = 0.15. An apple costs $0.15. An orange costs $0.10.