James is 8 years old. Last year, his father was 4 times as old as he was. In how many years' time will their combined age be 51?
1 answer:
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Answer:
x = 2
Step-by-step explanation:
If ΔABC~ΔAED then:
<u>the question is </u> Calculate the value of the copper in the coin
Step 1
Find the volume of the coin
we know that
the volume of a cylinder is equal to
where
r is the radius of the coin
h is the thickness of the coin
in this problem we have
Diameter=19 mm=1.9 cm
r=D/2------> r=1.9/2=0.95 cm
h=1.5 mm=0.15 cm
substitute the values in the formula
Step 2
<u>Find the mass of copper in the coin</u>
we know that
the density is equal to
Solve for the mass
we have
substitute in the formula
Step 3
<u>Find the cost</u>
we know that
the market price of the copper is $2.15 per pound
1 pound=453.592 grams
convert gram to pounds
3.785 gr=3.785/453.592=0.0083 pounds
0.0083*$2.15=$0.018=$0.02
therefore
<u>the answer is</u>
$0.02