There are 5 red socks and 5 black socks in a drawer. if david picks socks without looking, how many socks does he need to pick in order to be sure of getting one pair of socks?

He needs to pick at least 3 socks, to get one sure pair.

Step-by-step explanation:

Number of red socks = 5

Number of black socks = 5

Total number of socks =  Red socks +  Black Socks = 10

Now, If David wants to pick a sock randomly, the sock can either be red or black.

Since there are only 5 red and 5 black,

So, he needs to pick at least 3 socks, so that out of 3 , any 2 are of the same color.

picket out socks can be

(Red, Red, Black.) (Black, Black, Red), (Red, Black, Black) ,

(Black, Red, Black), (Red, Black, Red) and so on..

solution:

→c= a b , that is product of a and b is possible only when when a is m × n matrix and b is n × p matrix.

that is, number of columns of a= number of rows of b.

so, size of matrix , c= a b is , if a = (m × n)matrix

b= (n × p)matrix

then a b = [ (m × n)matrix] ×[   (n × p)matrix ]

→→c= a b= [m × p ] matrix

→→size of product a b will be equal to = number of rows of a × number of columns of b