The graph shows how many cans of each type of cat food were sold one day. (view picture)

about what percent of all the cans sold contained chicken flavored food?

a. 30%
b. 60%
c. 45%
d.10%

It's very easy!
.
First of all, add up all the amounts of all can flavors.
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What do you think it approximates to?
.
I'd say 245.
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Now, how much is 30 out of 245?
.
Around 24%.
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So, what's 245/100? (100 because it is default maximum percentage number)
.  
2.45.
.
24 divided by 2.45?
.
Around 9%.
.
Your best guess is 10% or D.

It will be a whole number.