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By what percent will a fraction change if its numerator is decreased by 30% and its denominator is decreased by 20%?

2 Answers

3 votes

Answer:

Decreased 12.5%

Explanation:

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User Ohad Zadok
by
5.5k points
3 votes

Answer: 12.5%

Explanation:

Let the original fraction is
(x)/(y)

After decreasing its numerator by 30% and denominator by 20%,

New fraction =
\frac{x-30\%\text{ of} x}{y-20\%\text{ of} y}

=
(x-(30x)/(100))/(y-(20x)/(100))

=
((100x)/(100)-(30x)/(100))/((100y)/(100)-(20x)/(100))

=
((100x-30x)/(100))/((100y-20y)/(100))

=
((70x)/(100))/((80y)/(100))

=
(70x)/(80y)

=
(7x)/(8y)

Thus, the total percentage change in the original fraction,

=
\frac{\text{original fraction-new fraction}}{\text{original fraction}} * 100

=
((x)/(y) -(7x)/(8y) )/((x)/(y) ) * 100

=
(1 -(7)/(8) )/(1 ) * 100

=
(8-7)/(8)* 100

=
(100)/(8) = 12.5\%

User Daniel Rosenthal
by
4.5k points