You have 8 people, you have 2 groups of 4.
8!/4!4!
=(8*7*6*5*4*3*2)/(4*3*2*4*3*2)
=(8*7*6*5)/(4*3*2)
=7*6*5/3
=7*2*5
=70
It's been a few years since I've done this. If you haven't learned how to do this type of an equation yet, then I'm probably wrong.
You want to know how long it'll take for the bacteria to grow
to (800/500) = 1.6 times their initial population.
The number of double-times it'll take is
[ log(1.6) / (log(2) ] = 0.6781 .
The double-time for these particular critters is 12 hours,
so it'll take them
0.6781 x 12 hours = 8.137 hours
= 8 hours 8.2 minutes .
Answer: a's value is (6,8) B is (-3,7), and C is (-7,-2)
