Answer:
c
Step-by-step explanation:
took the test
Solution:
As, in a pack of cards, there are 26 black cards and 26 red cards.
Probability of an event = 
Probability of drawing a black card from a pack of 52 cards = 
As each card drawn is replaced,Each black card draw is an independent with another black card draw.
Probabilities of drawing a black card on each of four trial=
![\frac{1}{2}\times \frac{1}{2}\times \frac{1}{2}\times \frac{1}{2}=[\frac{1}{2}]^4](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%5Ctimes%20%5Cfrac%7B1%7D%7B2%7D%5Ctimes%20%5Cfrac%7B1%7D%7B2%7D%5Ctimes%20%5Cfrac%7B1%7D%7B2%7D%3D%5B%5Cfrac%7B1%7D%7B2%7D%5D%5E4)
15^5 is 759,375
..........................
Answer:
20 hours
Step-by-step explanation:
first calculate volume:
12x10x3=360
then divide by 18
360/18=20
So 20 hours in total