SOLUTION: For a wedding, Shereda bought several dozen roses and several dozen carnations. The roses cost $15 per dozen, and the carnations cost $8 per dozen. Shereda bought a total of 17 doz

Algebra ->  Test -> SOLUTION: For a wedding, Shereda bought several dozen roses and several dozen carnations. The roses cost $15 per dozen, and the carnations cost $8 per dozen. Shereda bought a total of 17 doz      Log On


   

Question 294260: For a wedding, Shereda bought several dozen roses and several dozen carnations. The roses cost $15 per dozen, and the carnations cost $8 per dozen. Shereda bought a total of 17 dozen flowers and paid a total of $192. How many roses did she buy?
Answer by blwinbbbles(106) About Me  (Show Source):
You can put this solution on YOUR website!
So we have two equations: r = roses c= carnations
1) r + c = 17
2) 15r + 8c = 192
Use substitution: so take equation 1 subtract r from both sides and make it
c = 17 - r Now sub it into equation 2
15r + 8(17-r) = 192
15r + 136 - 8r = 192
7r + 136 = 192 subtract 136 from both sides
7r = 56 divide by 7
r = 8 now use r = 8 in equation 1
8 + c = 17
c = 9
so you will have 8 dozen roses and 9 dozen carnations