Let's say that in the beginning he weighted x and at the end he weighted x-y, y being the number of kg he wanted to loose.

first month he lost
y/3

then he lost:
(y-y/3)/3
this is
(2/3y)/3=2/9y
explanation: ((y-y/3) is what he still needed to loose: y minus what he lost already

and then he lost
(y-2/9y-1/3y)/3+3 (the +3 is his additional 3 pounts)
(y-2/9y-1/3y)/3-3=(7/9y-3/9y)/3+3=4/27y+3

it's not just y/3 because each month he lost one third of what the needed to loose at the current time, not in totatl

and the weight at the end of the 3 months was still x-y+3, 3 pounds over his goal weight!

so: x -y/3-2/9y-4/27y-3=x-y+3

we can subtract x from both sides:
-y/3-2/9y-4/27y-3=-y+3
add everything up:

-19/27y=-y+6

which means
-19/27y=-y+6

y-6=19/27y

8/27y=6
4/27y=3
y=20.25

so... that's how much he wanted to loose, but he lost 3 less than that, so 23.25

ps. i hope I didn't make a mistake in counting, let me know if i did. In any case you know HOW to solve it now, try to do the calculations yourself to see if they're correct!

5 0

3 years ago

What is the value of f(x)=-4 ?

Gala2k [10]

Answer : 2

Step by step walkthrough:

7 0

3 years ago