Answer:
Step-by-step explanation:
Given the function f(m)=20-0.25m to represent the amount of money f(m) she has left after talking m minutes, the zero of the equation can be gotten by setting f(m) to 0
f(m)=20-0.25m
0 =20-0.25m
-20 = -0.25m
m = -20/-0.25
m = 80
Hence Trudy will have talked for 80minutes if she has no money left
You simplify both sides and isolate the variable.
The surface area would be 26.5487 m².
The surface area of a cylinder is equal to the area of the circles at both ends, added to the area of the rectangular portion in the middle. The rectangle in the middle has a width equal to the circumference of the circle and a length equal to the height of the cylinder.
The circumference of a circle is given by C = πd, and the area of the circles is given by A=πr².
Since the height is in meters, we will convert it to cm. 3.5 m = 350 cm.
The diameter is 190 cm, so the radius is 190/2 = 95 cm.
This gives us:
SA = 3.14(190)(350)+2(3.14)(95)²
= 208810 + 56677 = 265487 cm² = 26.5487 m²