SOLUTION: A is directly proportional to B. When A is 7, B is 2. What is B when A is 10? P is inversely proportional to Q. P is 5 when Q is (1/10). What is P when Q is 0.01? I am confused

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Question 139970: A is directly proportional to B. When A is 7, B is 2. What is B when A is 10?
P is inversely proportional to Q. P is 5 when Q is (1/10). What is P when Q is 0.01?
I am confused? Do you set this up as a cross multiplication? Please help. Thankyou Bill
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
A is directly proportional to B.
A = kB
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When A is 7, B is 2.
Use this information to solve for "k":
7 = k*2
k = 7/2
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Therefore the equations that relates A and B is A = (7/2)B
What is B when A is 10?
10 = (7/2)B
B = 20/7
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Next Problem:
P is inversely proportional to Q
P = k/Q
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P is 5 when Q is (1/10)
5 = k/(1/10)
k = 1/2
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EQUATION:
P = 1/(2Q)
What is P when Q is 0.01?
P = 1/(0.02)
P = 50
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Cheers,
Stan H.