X=numbers of hammers
y=numbers of scewdrivers
f(x,y)= total cost in $
f(x,y)=11x+6.65y
f(4,7)=4(11)+6.65(7)=44+46.55=90.55
Sol: an expresion for the total cost of the tools is f(x,y)=11x+6.65 y;
x=number of hammers
y= number of scewdrivers.
The total cost is $90.55
This sets up as a very commonly used proportion.
90 oz / 18.95 = 1 oz / x Cross multiply
90 x = 18.95 Divide by 90
x = 18.95 / 90
x = 0.21 dollars or 21 cents.
So each ounce of shampoo costs 0.21 dollars or 21 cents.
This is a very handy way to check best deals. Stores have trained us for years to believe that the more we buy of a brand, the better the price. It isn't always true. Sometimes buying the smaller quantity is the better deal. There is only one way to be sure and that's to do a proportion like this one.
Try this is an example. The same company makes a smaller container of shampoo of 45 oz for 9.15. How much is 1 oz and which is the better deal? You should get 0.20333 dollars so this is marginally (just) the better deal.
Answer:
24 liters of 20% alcohol
Step-by-step explanation:
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