Question

Dr. Wellbee advised his patients to drink 8 eight-ounce glasses of water every day for every 50 pounds of weight. Kelby drank 168 glasses of water in one week. How much did Kelby probably weigh?

Answer 1

150 pounds

Explanation:

We require to calculate how many glasses of water Kelby drank per day.
Since there are 7 days in 1 week, if we divide 168 by 7 this will give us how much he drank each day.

`rArr168÷7=24`

We are told he has to drink 8 lasses each day for every 50 pounds of weight.

Since `24=3xx8` then his weight is approximately

`3xx50=150" pounds"`

Answer 2

150 lb

Explanation:

`color(blue)("Note about the method")`

`color(green)("If you are not sure how to go about solving a question of this type")` `color(green)("look at the units of measurement. What you have to do to all of")` `color(green)("them to end up with just the ones for the answer you also have to")` `color(green)("do to the numbers")`

'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Let unit of weight in pounds be lb
Let unit of day be d
Let unit of glasses be g

8 glasses per 50 lb`-> 8/50 color(green)((g)/(lb)) -> "Per day "->8/50color(green)((g)/(lbcolor(white)(.)d))`

This configuration of the units of measurement will not give what we need so turn the whole thing upside down giving:

`" use as " 50/8color(green)(color(white)(.)(lbcolor(white)(.)d)/g)`
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
168 glasses in 1 week
1 week = 7 days

`=> 168/7 color(green)(g/d) -> (168-:7)/(7-:7)color(green)(color(white)(.) g/d) = 24/1 color(green)(g/d)`
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`color(blue)("Putting it all together")`

`24/1color(white)(.) color(green)(cancel(g)/(cancel(d))) xx 50/8color(white)(.) (color(green)(lbcolor(white)(.)cancel(d))/(color(green)(cancel(g)))) larr" Just end up with weight"`

`(24xx50)/(1xx8)color(green)( lb) = 24/8xx50/1 = 3xx50=150color(green)(lb)`