Anyone know how to solve these problems?

[Maxmuscle27]

1) How Many Different Ways Can You Put On A Hat, Tie, And Then A Pair Of Shoes, If You Have 10 Different Ties, 20 Different Pairs Of Shoes, And 15 Different Hats?
A. 3000
B. 300
C. 45
D. 1500
E. 150



4) If Dr. Jones Has Seven Different Trees, How Many Different Combinations Of 3 Three Trees Can He Plant Outside Of His Mansion?

A. 30
B. 32
C. 33
D. 34
E. 35






If Figure Base “efcd” Is A Rectangle, Angle “aec” Is A Right Triangle With Angles 30-60-90 Degrees, Line “ec” Has Length 2 , And Line “ae” Has A Length Of 2, Then What Is The Length Of Line “ad”?
A.
B.
C.
D.
E.

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[tinman831]

First question you multiply the numbers together.

Second question the formula is Combinations: nCr = n!/[(r!)(n-r)!] ways can you pick r things out group of size n, order doesn't matter

Third question is beyond me.

 

[SMC2UCLA2_]

1)


If Figure Base “efcd” Is A Rectangle, Angle “aec” Is A Right Triangle With Angles 30-60-90 Degrees, Line “ec” Has Length 2 , And Line “ae” Has A Length Of 2, Then What Is The Length Of Line “ad”?
A.
B.
C.
D.
E.

did you happen to mean figure base "eacd" instead of "efcd"?

 

[Maxmuscle27]

did you happen to mean figure base "eacd" instead of "efcd"?

The third question I just copied and pasted it from a practice test I have...
So maybe the problem is just all wrong....

 

[Maxmuscle27]

First question you multiply the numbers together.

Second question the formula is Combinations: nCr = n!/[(r!)(n-r)!] ways can you pick r things out group of size n, order doesn't matter

Third question is beyond me.

I am not quite following you.

What does N(represent) and (Cr) and (r)... I don't recall ever seeing this formula.

 

[SMC2UCLA2_]

I am not quite following you.

What does N(represent) and (Cr) and (r)... I don't recall ever seeing this formula.

I could explain it but I think this website will serve you better
http://mathforum.org/dr.math/faq/faq.comb.perm.html

Cheers!