Question 1202921
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Answer: <font color=red size=4>4/9</font>


Explanation:


He has 3/5 of the white sugar left over, so 2/5 of it was used.
He also used up 1/2 of the brown sugar.


Normally when it comes to fractions we try to get the denominators to be the same (often the LCD). 
In this rare case, I'll make the numerators equal to a common multiple. 
I'll go with 2 as this common numerator.
2/5 stays the same
1/2 becomes 2/4


Dhruv used 2/5 of the white sugar and 2/4 of the brown sugar.
The reason I made the numerators the same was because he used an equal amount of sugar from each type. 
So that's why I want those '2's to match up.


He used up 2+2 = 4 parts of sugar out of 5+4 = 9 parts total.
Therefore we arrive at <font color=red size=4>4/9</font> to represent the fractional amount of sugar used.
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