Count the possible combinations of r letters chosen from the given list P. Q,R, S,T, U; r = 2

Step-by-step explanation:

The combinations are defined as

Where is the total number of elements and is the number of letter we are gonna picke, which is two. Using this information, we have

Therefore, there are 30 possible combinations of picking two letters.

step-by-step explanation:

given that ab is divided into equal parts as

ac, cd, de, ef, fg, gh, hi, ib.

from this we find that f is the midpoint of ab.

so using mid point formula we find

f = (3,7)

similarly considering fb, we get

h = mid point of fb = ((6,6) and g, mid point of fh is

g = (9/2, 13/2)

i is mid point of hb

so i =(15/2,11/2)