Both of the Billy’s parents (calling the parent billy) being tall is a recessive trait therefore both Billy’s parents has to have at least one recessive trait to make a tall child. Billy’s genotype would be way tt (aka recessive, recessive).
2 x 1/6 = 2/6 which can be reduced to 1/3
4 x 3/8 = 1 and 4/8 which can again be reduced to 1 and 1/2
problem 2 - 3/4
problem 3 - 2 (whole number)
Answer:
10 hours
Step-by-step explanation:
(150/x) + 1.5 + (450/(x+15)) = 600/x
Multiply through by x(x + 15):
150(x + 15) + 1.5x(x + 15) + 450x = 600(x + 15)
150x + 2250 + 1.5x^2 + 22.5x + 450x = 600x + 9000
150x + 2250 + 1.5x^2 + 22.5x + 450x - 600x - 9000 = 0
1.5x^2 + 22.5x - 6750 = 0
x = (-22.5 +/- sqrt(22.5^2 - 4(1.5)(-6750))) / (2*1.5)
x = (-22.5 +/- sqrt(506.25 + 40500)) / 3
x = (-22.5 +/- sqrt(41006.25)) / 3
x = (-22.5 +/- 202.5) / 3
x = 180/3 or -225/3
x = 60 or -75
But a negative number doesn't make sense, so therefore x = 60, so the journey took 600/60 = 10 hours.

means you shade the part above the line, and

means you shade the part under the line.
If it has an equal bar under it, like this:

, then you also shade the line, by making it solid instead of dotting it.