Answered

a drawer contains a mixture of red socks and blue socks, at most 1991 1991 in all. it so happens that, when two socks are selected randomly without replacement, there is a probability of exactly 1 2 12 that both are red or both are blue. what is the largest possible number of red socks in the drawer that is consistent with this data? (1991,



Answer :

The largest possible number of red socks in the drawer that is consistent with this data is 990.

To solve the given question, we will form equations according to the given data including a known and an unknown variable.

Let r be the number of socks that are red, and t be the total number of socks.

We get,

2(r(r-1)+(t-r)(t-r-1))=t(t-1)

Expanding the left hand side and the right hand side

we get,

4r^2-4rt+2t^2-2t = t^2-t

moving the terms, we will get that

4r^2-4rt+t^2 = t

We notice that the left side is a perfect square.

(2r-t)^2 = t

Thus t is a perfect square.

And, the higher t is, the higher r will be. So, we should set

t = 44^2

= 1936

we see, 2r-1936 = 44

We will use the positive root, to get that

2r-1936 = 44,

2r = 1980

r = 990

Therefore, we can conclude that the largest possible number of red socks in the drawer that is consistent with this data is 990.

To learn more about equations visit;

https://brainly.com/question/10413253

#SPJ4

Other Questions