Question 159819This question is from textbook
: Could I please ask for your help.
Jack earned twice as much as Mary and Jill earned $8 more than Mary. Who made the most money?
Jack
Mary
Jill
Can't Answer
A tire dealer sells 2 tires for as much as he paid for 3 tires. He paid $240 for a dozen tires. What is the total profit on 12 tires?
$120
$180
$240
$360
$385
This question is from textbook
Answer by nerdybill(7384)   (Show Source):
You can put this solution on YOUR website! Jack earned twice as much as Mary and Jill earned $8 more than Mary. Who made the most money?
.
Let M = amount Mary makes
then from: "Jack earned twice as much as Mary "
2M = amount Jack makes
and from: "Jill earned $8 more than Mary"
M+8 = amount Jill makes
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Notice that it would "appear" that 2M (the amount Jack makes) would be the most-- but, be careful...
What if M <= $8, say Mary makes $7
then 2M = $14 (Jack)
and M+8 = $15 (Jill)
Here, Jill makes the most.
.
But if M = $9,
2M = $18 (Jack)
M+8 = $17 (Jill)
.
Conclusion:Can't Answer
.
.
A tire dealer sells 2 tires for as much as he paid for 3 tires. He paid $240 for a dozen tires. What is the total profit on 12 tires?
Cost per tire: 240/12 = $20
Let P = profit of a single tire
.
2(20+P) = 3(20)
40+2P = 60
2P = 20
P = $10
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Therefore, profit on 12 tires: 12*10 = $120
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