Answer: 4
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Explanation:
1/2 = 4/8 after multiplying top and bottom by 8
So the mixed number 7 1/2 is the same as 7 4/8
We can convert to an improper fraction like so
7 4/8
7 + 4/8
7*(8/8) + 4/8
56/8 + 4/8
(56+4)/8
60/8
Notice how dividing 60 over 8 leads to 7 remainder 4. Think of it like having 60 cookies and you want to share them amongst 8 friends. Each friend gets 7 whole cookies (7*8 = 56 taken so far) and then we have 60-56 = 4 left over as the remainder.
Through similar steps, you should find that the mixed number 1 7/8 converts to the improper fraction 15/8.
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To rephrase the problem with improper fractions would be to say:
"The electrician needs to buy 60/8 feet of wire. There are 15/8 feet of wire in each spool. How many spools should the electrician buy?"
Let x be the answer to that question.
We multiply the number of spools (x) by the amount of feet of wire per spool (15/8) to get the expression (15/8)x
Set this equal to the target 60/8 and solve for x
(15/8)x = 60/8
15x = 60 .... multiply both sides by 8 to clear out the fractions
x = 60/15
x = 4
The electrician needs to buy exactly 4 spools
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A different approach could have us convert each mixed number into decimal form
7 1/2 = 7 + 1/2 = 7 + 0.5 = 7.5
1 7/8 = 1 + 7/8 = 1 + 0.875 = 1.875
So the electrician needs to buy 7.5 ft total and each spool has 1.875 ft of wire.
Using the same idea as before, we would then have,
1.875x = 7.5
x = (7.5)/(1.875)
x = 4
