Some beads were in a box. Anne used 17 of them. Then there were 56 beads in the box. How many were in the box to begin with?
1 answer:
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3
To calculate a fraction of a quantity, multiply the quantity by the numerator of the fraction and divide by the denominator
of 20 = (3 × 20 )/4 =
= 15
of 20 = (3 × 20 )/5 =
= 12
Answer:
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Explanation:
r = number of red pens
4r = cost of buying r red pens
example: if r = 10, then 4r = 4*10 = 40 is the total cost of buying 10 red pens
If John buys r red pens, then he must buy 20-r black pens so that r and 20-r add to 20.
John buys 20-r black pens, and at $5 each, so it will cost 5(20-r) dollars for just the black pens alone.
In total, John spends 4r + 5(20-r) dollars for all the pens (red & black)
We want $92 be the most he spends. This is the ceiling or highest value possible.
Therefore,
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Extra info:
If you want to solve for r, then
distribute
add r to both sides
subtract 92 from both sides
So John must buy at least 8 red pens. The most he can buy is 20 red pens since he wants 20 pens total.