Question

Ray is late for work, but would like to drink some coffee before he leaves. The coffee in the pot is too hot, so Ray puts 20 small ice cubes in a mug before pouring in the coffee. The ice cubes measure 1 cm per side. The mug is cylindrical, and has a height of 9 cm and a base of 7 cm. What is volume of the coffee that will fill the mug after the ice cubes have been added (round to the nearest whole number)?
A) 113 cm3.
Eliminate
B) 326 cm3.
C) 346 cm3.
D) 424 cm3.

Answer 1

B) 326 cm3.
The volume of the mug is $\pi r^{2} *h$
r - radius,
h - height

The radius of the mug is 7/2 (half the base) = 3.5cm

volume of the mug = 3.5^2 * PI * 9 = 346 cm3

20 ice cubes = 20 cm3 that you need to substract from 346, that gives 326 cm3.

Answer 2

The volume of the mug is the area of its base · the mug's height, or $\pi r^{2}$ h. This is 3.5 cm · 3.5 cm. · 9 · $\pi$, or 346.2 $cm^{3}$. The volume of each ice cube is 1 cubic centimeter, so 20 of them will occupy 20 $cm^{3}$. This leaves 326 $cm^{3}$ for the coffee.