Answer:
The cost of one ft2 of grass sod: $6
The cost of one geranium: $10
Explanation:
Let's call the cost of one grass sod x, and the cost of 1 geranium y. Then, we get the equations 10x + 10y = 160, and 6x + 12y = 156. Divide the first equation by 10 and the second by 6 to get x + y = 16 and x + 2y = 26. Subtract the first equation from the second to get that y = 10, so x = 6.