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A pizza place offers 4 different cheeses and 10 different toppings. In how many ways can a pizza be
made with 1 cheese and 3 toppings?

a.480
b.360
c.240
d.120


How many ways can you purchase 3 CDs if there are 3 to choose from, 4 cassettes if there are 7 to
choose from, and 2 DVDs if there are 4 to choose from?

a. 190
b.200
c. 210
d. 220


How many ways can you purchase 2 CDs if there are 3 to choose from, 4 cassettes if there are 4 to
choose from, and 2 DVDs if there are 5 to choose from?

a. 60
b. 50
c. 40
c. 30

Respuesta :

For the first one:

4C1 X 10C3 = 480

Second one:

3C3 X 7C4 X 4C2 = 210

Last one:

3C2 X 4C4 X 5C2 = 30
unigeek51
) (4 choose 1)(10 choose 3) = 4*10*9*8/6 = 480 

2) (3 choose 3)(7 choose 4)(4 choose 2) = 1*(7*6*5/3!)(4*3/2) = 210

you do the last one its 30.

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