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Here we have a solution to Favorite Pets
from some 6th graders: Chrissy, Dajouna, Thurmeka, and Antoine at the
Madison Ave. Baptist Academy in Paterson, NJ.
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Solution:
Fifteen (15) kids had to choose between pot-bellied pigs,
capybaras, cocatiels and turtles. First, we figured out what the
percentages were as fractions. 20% is 1/5; 120% is 1 1/5 (100% is
equal to 1 and 20% is equal to 1/5. 1 + 1/5 = 1 1/5).
1/3 of the children liked turtles. So, we had 1/3 and we
multiplied it by 15 and got 5. Then, since 120% of the kids who liked
turtles liked capybaras, we multiplied 1/3 by 1 1/5 and we got 2/5,
which is the fraction of the students who preferred capybaras. 20% of
the number of students who liked turtles liked cockatiels. So, we
multiplied 1/3 by 1/5 and we got 1/15.
We added 2/5, 1/15, and 1/3 and we got 12/15. We subtracted
12/15 (the students counted so far) from 15/15 (all the students) and
got 3/15 and reduced it to 1/5. 1/5 is the fraction of the students
who preferred pot-bellied kids.
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Okay, notice how these kids changed the
percentages to fractions so they worked just with one or the other.
Good idea. Also, notice when (at the end of the second paragraph)
they multiuplied two fractions together. Does that make sense?
Only one obvious problem, and that's a
curious typo at the very end!!
You know, you can answer these questions
too! Just write to
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