16 POINTS!! The solid in the diagram has a surface area of 18 units2. If a cube is added on the green face, what will the new su
rface area be? A) 20 units2 B) 21 units2 C) 22 units2 D) 23 units2
1 answer:
The complete question in the attached figure
Let
x------> length side of a cube
we have that
[surface area original]=18 units²
surface area original=x²*[number of faces]
number of faces=2*[4+4+1]-----> 18 faces
surface area original=x²*[18]
18=18*x²-------> x²=18/18---------> x=1 unit
<span>If a cube is added on the green face,the new surface area will be
</span>18+4*[area of one faces]-----> 18+4*1²----> 22 units²
the answer is
22 units²
Let
x------> length side of a cube
we have that
[surface area original]=18 units²
surface area original=x²*[number of faces]
number of faces=2*[4+4+1]-----> 18 faces
surface area original=x²*[18]
18=18*x²-------> x²=18/18---------> x=1 unit
<span>If a cube is added on the green face,the new surface area will be
</span>18+4*[area of one faces]-----> 18+4*1²----> 22 units²
the answer is
22 units²
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Label one column age now and the other age in 5 years.
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We do know that the man's age is 4 times the son's age.
So the man's age will be 4x.
In the age in 5 year column, we add 5 to their current ages.
Now set up our equation.
Since it says "in five years" we use information in second column.
In 5 years time, he, "4x + 5", will be, equals,
3 times as old as his son, "3(x + 5)".
So we have 4x + 5 = 3(x + 5).
Solving from here, we find that x = 10.
So the son is 10 and the man is 4 times his age or 40.
