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0.49f + 0.34p = 5.00 solve for f and p

0.49f + 0.34p = 5.00 solve for f and p-example-1
User Lakesha
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1 Answer

4 votes

Since the total cost must be $5, the we have the following equation which relates the postacard and first class staps:


0.49f+0.34p=5

where f denotes the number of first class stamps and p the nunber of postcard stamps.

Now, we need to solve for f. Then, by moving 0.34p to the right hand side, we have


0.49f=5-0.34p

and by dividing both sides by 0.49, we get


f=(5)/(0.49)-(0.34)/(0.49)p

or equivalently


f=(5-0.34p)/(0.49)

Now, we need to solve for p. Then, by moving 0.49f to the right hand side, we obtain


0.34p=5-0.49f

and by dividing both sides by 0.34, we get


p=(5-0.49f)/(0.34)

Finally, we have that f=7 and we need to find p. In this regard, this last equation must help us. By substituting f=7, we have


p=(5-0.49(7))/(0.34)

which gives


\begin{gathered} p=(5-3.43)/(0.34) \\ p=(1.57)/(0.34) \\ p=4.617 \end{gathered}

By rounding up this result, the number of postcard stamp is 5.

In summary, the answers are


\begin{gathered} f=(5-0.34p)/(0.49) \\ p=(5-0.49f)/(0.34) \\ \text{and} \\ 5\text{ postcard stamps} \end{gathered}

User Levigroker
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7.1k points