Question

A golf ball weighs about 45.9 grams. About how many ounces would a dozen golf balls weigh?

Answer 1

I've set up a conversion equation:

You can just say it out loud what you're trying to do and that will help you write out your ratios.

45.9 grams per 1 ball
1 ounce per 28.35 grams
We have 12 balls

`(45.9g)/(ball)*(1oz)/(28.35g)*12(ball)`

`(45.9cancelg)/(cancel(ball))*(1oz)/(28.35cancelg)*12(cancel(ball))`

`=(45.9*12)/28.35~~19.4oz`

Answer 2

so the weight of 12 balls is 19.43 ounces rounded to 2 decimal places

Explanation:

Using Matt B's conversion

1 ounce per 28.35 grams
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`color(blue)("Determine the weight of 12 balls in grams")`

Given:`" "`1 ball weighs 45.9 grams

Expressing this as a ratio for 12 balls:

`("ball count")/("total weight") = 1/(45.9" grams")`

So for 12 balls we have `(12xx1" balls")/(12xx45.9" grams") = (12" balls")/(color(red)(550.8" grams"))`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

`color(blue)("Converting the grams to ounces")`

If 1 ounce is the same weight as 28.35 grams then again by using ratio:

`("ounces")/("grams") ->1/28.35 -=(1-:28.35)/(28.35-:28.35) = (color(green)(1-:28.35))/1`

I have not completed the division on the top yet as this will introduce rounding errors.

So `color(green)("each gram is worth "1-:28.35=" ounces")`, but we have `color(red)(550.8" grams")`

So `" " (12" balls")/(color(red)(550.8" grams")) =(12"balls")/(color(red)(550.8)color(green)(xx1-:28.35))`

`=" "(12" balls")/(19.4285..."ounces"`

so the weight of 12 balls is 19.43 ounces rounded to 2 decimal places