Question

Set B has 12 elements in it and set C has 7 elements in it Answer the following:
1. What is the maximum number of elements that could be in the intersection of sets B and C?
2. What is the minimum number of elements that could be in the intersection of sets B and C?

Answer 1

My answer is #1. maximum: 7 minimum: 5

Answer 2

Yes to the first, no to the second... what if they have no elements in common? :P

Answer 3

1. Consider this:
{1,1,1,1,1,1,1,1,1,1,1,1} and {1,1,1,1,1,1,1}

2. Consider this:
{1,1,1,1,1,1,1,1,1,1,1,1} and {2,2,2,2,2,2,2}

Answer 4

What @PeterPan said.

Remember that the intersection is the set of common elements.

Answer 5

so the minimum could be zero

Answer 6

That's right :D

Answer 7

Yay!

Answer 8

thanks guys could you help me with another question

Answer 9

Sure :-)

Answer 10

NO >:(
LOL JUST KIDDING GO AHEAD

Answer 11

A birthday cake is in the shape of a right circular cylinder and with a diameter of 30cm and a height of 12cm. A piece in the shape of a sectoral wedge with central angle 22.5 degrees is cut from the center of the cake. Draw the cake and the piece cut from it. Then using II = 3.14, find:
1. What is the volume of the piece cut from the birthday cake?
2. What is the surface area of the piece cut from the birthday cake?
3. After the piece has been taken out, what is the volume of the remaining part of the cake?
4. After the piece has been taken out what is the surface area of the remaining part of the cake?

Answer 12

@PeterPan and @ParthKohli ru guys still there?

Answer 13

So many numbers o.O

Answer 14

First, we might wanna know what the volume of the entire cake is... can you find it? :)

Answer 15

V=II*r^2*h
V= 3.14*15^2*12
V= 3.14*225*12
V = 8478 cm3

Answer 16

@PeterPan

Answer 17

Okay :D
Now, we wanna know what part of the cake has been taken away in the slice :D
So, the angle it makes is 22.5 degrees? the whole cake is 360 degrees...
What's 22.5 / 360?

Answer 18

.0625

Answer 19

That's right :)
So the volume of the slice is this times the volume of the cake :D

Answer 20

.0625*8478=529.875

Answer 21

And that's the volume of your cake :D

Answer 22

the slice, at least :D

Answer 23

whats next
how do we find surface area

Answer 24

Surface area is a bit tricky... where to begin...
Area of a sector? :D
That's just a fancy name for area of a slice of a circle...

Answer 25

whats the formula

Answer 26

can you draw out the cake pls

Answer 27

formula for the area of a sector is area of the circle times (angle of sector/360)

Answer 28

44.15625

Answer 29

steps?

Answer 30

22.5/360*3.14*15^2

Answer 31

Seems reasonable :D
Now, there's a sector this size on top and at the bottom, right? so double this area :D

Answer 32

88.3125

Answer 33

Now, there are two rectangles, the sides of the slice, with length equal to the height of the cake and width equal to the radius. What's the area of that rectangle?

Answer 34

where does the rectangle come from?

Answer 35

hello @PeterPan

Answer 36

Because there when you slice the cake, it looks like this