4 pencils and 3 crayons are 20.9 inches. 5 pencils and 4 crayons are 26.5 inches. Each pencil isthe same length as the other pencils, and each crayon is the same length as the other crayons. What is the length of 1 pencil? What is the length of 1 crayon?
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4 pencils and 3 crayons are 20.9 inches. 5 pencils and 4 crayons are 26.5 inches. Each pencil isthe same length as the other pencils, and each crayon is the same length as the other crayons. What is the length of 1 pencil? What is the length of 1 crayon?
4P + 3C = 20.9 both sides x4 —> 16P + 12C = 83.6 (eq 1)
5P + 4C = 26.5 both sides x3 —> 15P + 12C = 79.5 (eq 2)
subtract (eq 2) from (eq 1) P = 4.1
substitute 4.1 back into (eq 1) (4)(4.1) + 3C = 20.9
16.4 + 3C = 20.9
3C = 4.5
C = 1.5
check answer
substitute both back into (eq 2)
Does (5)(4.1) + (4)(1.5) = 26.5 ?
20.5 + 6.0 = 26.5 ?
26.5 = 26.5 True
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