Ivan can paint 25 square feet every half hour. In 3 hours, there are 6 half-hour intervals (since 3 hours × 2 half-hours per hour = 6 half-hours).
To find out how many square feet he can paint in 3 hours, we can multiply the number of half-hour intervals by the amount he can paint in each interval:
\( 6 \text{ half-hours} \times 25 \text{ square feet per half-hour} = 150 \text{ square feet} \).
So, Ivan can paint 150 square feet in 3 hours.
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