amazingxin777

thank you!!!

hint: for this problem you would use combination instead of permutation (because order doesn't matter).

there is an answer here (if you have an account on Chegg.com)

https://www.chegg.com/homework-help/questions-and-answers/volume-parallelepiped-determined-three-dimensional-vectors-b-c-11-find-volume-parallelepip-q14120625

104 is the answer

Hint 1:

the third angle is 30

Hint 2:

In a 30-60-90 triangle, the hypotenuse is twice the length of the side opposite the 30 degree angle.

Hint 3:

In a 30-60-90 triangle, the side opposite the 60 degree angle is \(\sqrt 3\) times the side opposite the 30 degree angle.

you should be able to figure it by now

if not i can finish the problem

Oh got it

my username on aops is amazingxin777 (same as this one)

Just continue on the sequence

\(1\text {st} \space \text {term}\)      \(2\text {nd} \space \text {term}\)       \(3\text{rd}\space\text{term}\)       \(4\text{th} \space \text{term}\)        \(5\text{th} \space \text{term}\)        \(6\text{th} \space\text{term}\)        \(7\text{th} \space \text {term}\)      \(8\text {th} \space \text{term}\)      \(9\text{th} \space \text{term}\)      

20 (even)      10 (even)          5 (odd)            16 (even)           8 (even)           4 (even)           2 (even)         1 (odd)           4 (even)

\(10\text{th} \space\text{term}\)

         2 

So the answer is \(\boxed {2}\)

hint: \(\text {distance} =\) \(\text {speed} \times \text {time}\)