6/8a+4,6-2/4a. I think that this is the answer.
Answer:

Step-by-step explanation:
The probability for a flip on either side of the coin is always 50% or 
So to get the probability for the three flips just do:
or
×
× 
Either way you solve it the answer is 
Two fifths are 4 one fourth is 2 so there are 2 red guppies the fraction that they are red is 2 over 4 the fraction that are not red are 2 over 4 too
x 12
the 12 in the numerator (top) and the 12 in the denominator (bottom) cross out so you are left with 50.
Answer: 50
D. Customer who buy at least 25 tickets will pay $1.50 each