Question 226300
Joe Lick bought some 20-cent and 25-cent stamps. He bought 32 stamps in all, and paid $7.40 for them. How many stamps of each kind did he buy?


Step 1.  Let x be the number of 20-cent stamps


Step 2.  Let 32-x be the number of 25-cent stamps since there are 32 stamps in all.


Step 3.  Let 0.20x be the dollar value of 20-cent stamps.


Step 4.  Let 0.25(32-x) be the dollar value of 25-cent stamps.


Step 5.  Then, 0.20x+0.25(32-x)=7.40 be the total dollar value of 7.40.


Step 6.  Solving the equation in Step 5 yields the following steps:


*[invoke explain_simplification "0.20x+0.25(32-x)=7.40" ]


With x=12 then 32-x=20


Check the total dollar value  0.20*12 + 0.25*20 =2.40+5.00=7.40 which is a true statement.


Step 7.  ANSWER:  The number of 20-cent stamps is 12 and the number of 25-cent stamps is 20.


I hope the above steps and explanation were helpful.


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Respectfully,
Dr J

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