Math word problem

Question

mr ohi is monitoring his sodium intake so he switched to drinking low sodium v8 juice. Regular v8 juice has 420mg of sodium per 8oz serving whereas low sodium v8 juice has 141mg of sodium per 8oz of serving. what is the percent of decrease in the amount of sodium intake per serving? round to whole number 

Answer 1

Hi Jocelyn!  It looks like we have two numbers to work with and two "Big ideas" to remember to use here: finding a percent and finding how something has changed.

 

We typically find how something has changed using subtraction -- specifically by taking the 'Ending value' minus the 'Starting value' (End-Start).  What's nice about this problem is that we're asked for the Decrease specifically, so we already know that something went down.  We aren't so concerned about what the specific Sign of the change will be, only about the Size of the change.  So this is like taking the absolute value of the change, which we do by just doing "bigger minus smaller" like we're used to doing when subtracting.  Ok so far?  First big idea done. |141-420|=420-141.

 

Percents can be found a lot like the way we'd find the fraction for something -- "how much you want 'over' (meaning divided by) how many there originally were."  In this problem we want the Decrease, which we just found, and we Originally had the regular v8 juice.  So now we're almost done!  There are many ways to turn that fraction (or decimal if you punched them into the calculator) into a percent.  I'll leave that for you to ask if you're still stuck. I'm guessing that rounding will be pretty simple to do once you get the percent.  Let me know if you need more help.