Final answer:
The original positive number a is larger than the same number increased by 50% and then decreased by 50%. This is because the latter operation effectively decreases the original number by 25%.
Step-by-step explanation:
The student asked which amount is larger and by how much: a positive number a, or the same number a increased by 50% and then decreased by 50% of the result. Let's calculate both scenarios:
Increasing a by 50% gives us a + (0.5 × a) = 1.5a.
Then, decreasing this result by 50% gives (1.5a) - (0.5 × 1.5a) = 0.75a.
Comparing the original number a with 0.75a, it's clear that a is larger because 0.75a is equal to a reduced by 25%.
Therefore, the original number a is larger than the result of increasing by 50% followed by a decrease of 50%, and it is larger by 25% of a.