Answers

2015-12-12T16:31:54+08:00
This is kind of a start at the end question. Wherein you solve the problem backwards. First she had 9 muffins:

1-\frac{2}{3}=\frac{1}{3}

Meaning that 9 is the one-third or the 33.33% of the original, so:
NV(the remaining)=Percentage x Original
9=\frac{1}{3} x Original
Divide both sides by one-third
27=original

now before she gave the two-third of the muffins to her niece, she has 27 pcs left.. but there is another problem, she gave 1/10 of muffins to her children that resulted to 27 pcs left... therefore we do it again:
1-\frac{1}{10}=\frac{9}{10}
meaning 27 is the nine-tenth value of the original so lets do what we did earlier by substituting it in the equation, 
NV=Percentage x Original
27=\frac{1}{10} x Original
Divide both sides by one-tenth
Original=30

She had 30 muffins baked before she gave it to the kids and to her nieces. Hope this helps =)

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