word problem...functions...MATH PEOPLE help...ten points for first right answer?

Question

OK, Let w(m) give the weight of an avg. sized baby girl who is m months old.

2. An 8-month baby girl weighs w(13) pounds. Is she of avg. weight, above avg., or below avg.? Justify your answer....and yes...it IS w(13) pounds...definately.

Ok, I pretty much think this is an inverse but I have absolutely no clue on how to solve it...HELP!

So far I've gotten all three here so I need the right answer...I'm leaning towards overweight but not sure...

can u explain in kinda detail why too?


THANKS!!!

Answer 1

If she is 8-months old, you would expect her weight to be w(8). But we are told she is w(13). This is the weight of an average 13 month old! So she weighs more than the average weight.

Answer 2

Since babies keep on growing from when they are born, the function w(m) should be increasing. This means that the baby will never lose a significant amount of weight as she grows months older.

Then if w(m) is increasing, then for any positive number x, w(x) < w(x+1)

So w(8) < w(9) < w(10) < w(11) < w(12) < w(13), which implies that w(8) < w(13).

The 8-month old baby girl SHOULD be w(8) pounds, but she is actually w(13). Then she is heavier than she should be.

Therefore, the baby girl is of above average weight.

Answer 3

An 8-month baby girl weighs w(13) pounds. Is she of avg. weight, above avg., or below avg.?

This means the 8-month baby has the weight of a 13-month baby. So she is over-weight as the function w should increase with time.

Answer 4

i know you asked for an answer but you definetly didnt give us enough info. From what you wrote, you pretty much just said that an 8 month old baby is 13 pounds. Is she above normal or under weight. this isnt a math problem.

Answer 5

You would expect an eight-month-old baby to weigh less than an older child, i.e.,

W(8) < W(13)

This baby weighs the same as a 13-month-old:

W(8) < W13) = the girls' weight

Note which side of the < she is on.