Answer:
Her son is 10 years old.
Step-by-step explanation:
Let son be x
Ellie is 4x
In 5 years time: Her son = x + 5
Ellie = 4x + 5
Given that she will then be 3 times as old as her son: 4x + 5 = 3(x + 5)
Solve x: 4x + 5 = 3(x + 5) ,4x + 5 = 3x + 15
x = 10
Answer:
58.33 lbs.
Step-by-step explanation:
There are already 25 lbs of alloy of copper
Of this 25 lbs, 20% is pure i.e. copper content = 25(0.5) = 5lbs.
Now available is
Copper Other metals
5 lbs 20 lbs
Let x lb of 30% copper is added.
Then new alloy will have 5+0.3x lb copper in total of 25+x lbs
Percentage pure = 
Simplify to get

Hence answer is 58.33 lbs should be added.
Answer:
X=? Sorry
Step-by-step explanation:
$745.42 because $375.98 - $38.56 = $337.42. Since Mr. Kent deposited $408.00 into his balance at the bank, $408.00 + $337.42 = $745.42.