Let n and d represent the numerator and denominator.
n/d is the original fraction.
d ≠ 0
Decrease the numerator by 50% to get 0.5n
Decrease the denominator by 25% to get 0.75d; notice how 100% - 25% = 75%. If you lose 25% of something then you keep the remaining 75% of it.
Divide the expressions mentioned.
(0.5n)/(0.75d) = (0.5/0.75)(n/d) = (50/75)(n/d) = (2/3)(n/d)
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Let's summarize:
The new fraction is 2/3 that of the original.
Therefore the fraction decreases by 1/3 which is roughly 33.333%. This is because 1 - (2/3) = (3/3) - (2/3) = (3-2)/3 = 1/3.
