Show your method used to solve problem.
If the cost of 5 roses, 9 irises and 6 carnations is the same as 3 carnations 6 irises and 8 roses find the cost of a single iris if it cost $42 for a dozen roses and a carnation is three-quarters the cost of an iris.
Let price of 1 rose, 1 iris and 1 carnation be R, I, and C, respectively
Then we can say that: 5R + 9I + 6C = 8R + 6I + 3C
8R - 5R + 6I - 9I + 3C - 6C = 0
3R - 3I - 3C = 0
3(R - I - C) = 3(0) ------ Factoring out GCF, 3
R - I - C = 0 ------- eq (i)
12R = 42
R, or cost of 1 rose = , or $3.50
_____ ------- Cost of 1 carnation is cost of an iris
R - I - C = 0 -------- eq (i)
-------- Substituting 3.5 for R, and for C in eq (i)
-------- Multiplying by LCD, 4
14 - 7I = 0
14 = 7I
Cost of 1 iris = , or