Answer: 30
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Step-by-step explanation:
Refer to the drawing below. I have a 2 by 5 grid of squares. So there are 2*5 = 10 squares total.
Four of those squares are shaded blue to represent the fraction
If Susan used 4 blue tiles (instead of 12), then she'd have 10 tiles total. This would mean 10 would be the answer.
However, she's using 12 blue tiles. The jump from 4 to 12 is "times 3". So we'll need to multiply that 10 by 3 as well.
10*3 = 30
If Susan uses 12 blue tiles, then she has 30 tiles total.
Notice that the fraction
is the same as
after multiplying both top and bottom by 3.
If you wanted, you can split a round cake into 10 equal slices. If a person eats 4 slices, then that represents the fraction
. Now imagine splitting each of those initial ten slices into three smaller pieces. If you manage to do so, then you'd have 30 very small slices. The four that the person ate would have effectively eaten 12 very small slices. So this is another way to see how
. Personally, when it comes to fractions, I prefer using a grid of squares because it's a bit tricky sometimes to divide up circles perfectly.