23.1 can be estimated to 23 rounded to 20.
19.24 can be estimated to 19 rounded to 20.
The answer would be 42 which would be rounded to 40.
The number of permutations of the 4 different letters, taken two at a time, is given by:
Answer:
9ab+3a
Step-by-step explanation:
2a*3b=6ab
2a*1=2a
a*3b=3ab
a*1=a
adding everything together=6ab+2a+3ab+a=9ab+3a