Acoin is flipped 50 times. in those 50 trials, 29 of the flips resulted in heads. what is the experimental probability of a coin flip resulting in tails?

If 29 of the flips resulted in heads then, 21 of them resulted in tails. The experimental probability of getting tails is the quotient when 21 (tails) is divided by the total sample space. The answer would be 21/50. 

I’m not so sure about this one.

The density of the cube is 40