$_{n}C_{r} = \frac{n!}{r!(n-r)!} \\ \\ _{11}C_{3}= \frac{11!}{3!*(11-3)!} =\frac{11*10*9*8*7*6*5*4*3*2*1}{3*2*1*8*7*6*5*4*3*2*1} =\frac{11*10*9}{3*2} =165 \\ \\_{11}C_{4}=\frac{11!}{4!(11-4)!} =\frac{11*10*9*8*7!}{4!*7!} =\frac{11*10*9*8}{4*3*2*1} =330$

7 0

2 years ago

Read 2 more answers

I need help with 3 please... I don’t know how to do it and I know my answer is wrong... please

harina [27]

It will take 20 hours I think because 8,16,32,64 is the sequence of cars waxed and 3,6,12,24 are the hours, 64 take 4 away = 60. and then 24, I took 4 away from 64 so it would be 20 if I took away 4

8 0

2 years ago

Write a word problem for the equation 3/4•1/2=3/8

Aleksandr [31]

Jessica is baking cookies for a bake sale and needed 3/4 cups of flower in the original recipe. Jessica's mom later found out that there wouldn't be as many guests so Jessica cut the recipe in half and needs half of the original amount of flour. Jessica now needs 3/8 cups of flour.

8 0

3 years ago

A section in a stained glass window is shaped like a trapezoid. The top base is 1 centimeter and the bottom base is 1.5 centimet

Alenkinab [10]

4.4 square centimeters.

8 0

2 years ago