For the first month it will be $40 for the service and $35 to activate the phone service. After the first month it will only be $40 but for the first month it will be $75
the hypotenuse may be found by using the Pythagoras theorem
Both sides are identical.
Each hour,
x makes b/6 bearings
y makes b/4 bearings
z makes b/3 bearings
Together, each hour, x, y and z together make
b/6+b/4+b/3=b(1/6+1/4+1/3)=b(2/12+3/12+4/12)=b(3/4)=3b/4 bearings.
Time to make b bearings =
b/(3b/4)=4/3 hours = 1 hour 20 minutes.
We have to find the mass of the gold bar.
We have gold bar in the shape of a rectangular prism.
The length, width, and the height of the gold bar is 18.00 centimeters, 9.21 centimeters, and 4.45 centimeters respectively.
First of all we will find the volume of the gold bar which is given by the volume of rectangular prism:
Volume of the gold bar 
Plugging the values in the equation we get,
Volume of the gold bar 
Now that we have the volume we can find the mass by using the formula,

The density of the gold is 19.32 grams per cubic centimeter. Plugging in the values of density and volume we get:
grams
So, the mass of the gold bar is 14252.769 grams