Question

Suppose x and y are two possitive numbers. Write an expression for their average, and then for the reciprocal of their average

Answer 1

what is the average of n numbers?

Answer 2

i dk am i dupposed to know or is it in the question

Answer 3

you are supposed to know.

Answer 4

suppose I had profits of 1000 dollars in one month and a profit of 500 dollars is the next month, what is my average profit for the two months?

Answer 5

in other words, what is my average profit per month?

Answer 6

750

Answer 7

okay, good. how did you figure that out?

Answer 8

doing good sugar haha (:

Answer 9

i added 1000 and 500 and divided by 2 to get the average

Answer 10

good.
so what if I told you that my profit for first month was 1000, second month was 500 and third month was 600. what is my average profit?

Answer 11

700

Answer 12

very good. what did you do to get that answer?

Answer 13

i added all three and divided it by three

Answer 14

good. so what if I told you my profit for the first month was x and my profit for second month was y, what is my average profit?

Answer 15

would it be x+y divided by 2

Answer 16

exactly! very good!

Answer 17

so your expression is average = (x+y)/2

Answer 18

if you had 10 numbers, then your average would be
(a+b+c+d+e+f+g+h+i+j)/10

Answer 19

where a,b,c... are the 10 numbers

Answer 20

ok and can u tell me how do i write the recipocal of the average

Answer 21

reciprocal of a number x is 1/x.
the reciprocal is a number, which when multiplied by x, gives you 1. 1 is called the multiplicative identity.
so, when you multiply x times 1/x, you get x/x = 1
similarly, what is the reciprocal of the number (x+y)/2 ?

Answer 22

ok i got it its 2/(x+y)

Answer 23

okay very good!

Answer 24

and one more quesion, for the same numbers x and y, write an expresiion for their average of their recipocals

how do i do that

Answer 25

what is the reciprocal of x?
what is the reciprocal of y?

Answer 26

x/1 and y/1 is that right

Answer 27

so if you multiply x times x/1 you will get 1? are you sure?

Answer 28

im srry 1/x and 1/y

Answer 29

okay good. so now you have two numbers 1/x and 1/y.
what is their average?

Answer 30

2/xy

Answer 31

no. thats wrong. the average of two numbers a and b is (a+b)/2
so what is the average of two numbers 1/x and 1/y?

Answer 32

(1/x+1/y)/2

Answer 33

okay. good. that is your answer.
you can simplify the expression further if you want, but that is the answer to your question.

1/x+1/y = (x+y)/xy
so (1/x+1/y)/2 = (x+y)/2xy

Answer 34

ok thank you

Answer 35

or rather, 2(x+y)/xy

Answer 36

no, its the first one. sorry.

Answer 37

ok thanks

Answer 38

(:

Answer 39

hey can u help me with another question math mind can u try

Answer 40

Andy drives 300 miles to Lake Tahoe at 70 miles per hour and returns home at 50 mph. What is his average speed for the round trip. (It is not 6o miles per hour.)

Write expressions for the time it takes for each leg of the trip if Andy drives a distance d, at speed r base 1 and returns at speed r base 2

Answer 41

post it up as a new question, it's better