Answer:
Use 49 ounces of the 14% allow and 41 ounces of the 23% alloy.
Step-by-step explanation:
Each ounce of the 14% copper contains 0.14 ounce of pure copper.
Each ounce of the 23% copper contains 0.23 ounce of pure copper.
Each ounce of the 18.1% copper contains 0.181 ounce of pure copper.
Use x ounces of the 14% and y ounces of the 23% to make 90 ounces of 18.1% alloy.
x+y = 90
y = 90-x
0.14x + 0.23y = 0.181·90
0.14x + 0.23(90-x) = 16.29
0.14x + 20.7 - 0.23x = 16.29
-0.09x + 20.7 = 16.29
4.41 = 0.09x
x = 49
y = 90-x = 41
Use 49 ounces of the 14% allow and 41 ounces of the 23% alloy.
A1 = 35x+25
Good guys = 40x
35x+25 = 40x
subtract 3x x from each side
25 = 5x
divide each side by 5
x = 25/5 = 5
so 5 hours they would be the same cost, anything over 5 hours and A1 would be better
so X>5 for A1 to be the better price
Answer:
b.
Use special characters like italics and underlining
Step-by-step explanation:
i took the test
U can see the answer in the picture below
