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4. A stamp collector has some 15¢ stamps and some 20¢ stamps. The number of 15¢ stamps is eight less than three times the number of 20¢ stam
Question
4. A stamp collector has some 15¢ stamps and some 20¢ stamps. The number of 15¢ stamps is eight less than three times the number of 20¢ stamps. The total value is $4. Find the number of each type of stamp in the collection. PLEASE SHOW WORK
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Mathematics
3 years
2021-09-04T11:55:14+00:00
2021-09-04T11:55:14+00:00 1 Answers
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Answer:
Step-by-step explanation: Let variable x represent the 15¢ stamps, and variable y represent 20¢ stamps.
x= 3y-8
0.15x+0.20y = 4
Replace x in the second equation by (3y-8)
0.15(3y-8) + 0.20y = 4
0.45y – 1.2 +0.20y = 4
Collect like terms;
0.45y+0.20y = 4+1.2
0.65y = 5.2
Divide both sides by 0.65 to solve for y;
y= 5.2/0.65
y = 8
Replace in equation ” x=3y-8 ” to solve for x;
x = (3*8) -8
x=24 – 8
x = 16
Therefore, the 15¢ stamps are 16 in number, and the 20¢ stamps are 8 in number.