1. A room contains one-hundred people. Each person has hair that is either black, blonde, brown or red in colour. There are as many people with black hair as there are people with blonde, brown or red hair. Write down a linear system of two equations in four unknowns that encodes this information, and also write down the corresponding augmented matrix.
So, the equations I got were: 25b+25l+25r+25d=100
b+l+r+d=100
is that correct? I am not sure.
Your 1st equation is not write at all, it does not make sense. 2nd one is correct as it is obvious. If your 3rd sentence is quite write then either b=l or b=r or b=d. (And in your 3rd sentence if you replace "or red" by "and red" then your equation becomes b+l+r+d=100, and b=l=r=d, but then solution is trivial b=l=r=d=25. )
1. A room contains one-hundred people. Each person has hair that is either black, blonde, brown...
22% of all people are blonde, 40% brown hair, 5% red hair, 20% black and the rest are other color. You select 10 people at one time. What is the probability you get 2 blonde, 3 brown, 2 red and 3 black hair?
There are 24 people. 9 have black hair, 4 have brown hair, 5 have blonde hair, and 6 have red hair. 3 people are then selected at random without replacement. Solve the following probabilities: (a) What is the probability that all 3 people selected have red hair. (b) What is the probability that 2 people selected have the same color hair color, and the other person selected has a different hair color