### Instruction: If Heidi can paint a wall in 45 minutes, what fractional part of the wall can she paint in 9 minutes?### Response: I want to find the fraction of the wall that Heidi can paint in 9 minutes, so I need to compare 9 minutes to 45 minutes.
One way to do that is to divide 9 by 45, which gives me 0.2.
That means that 9 minutes is 0.2 of 45 minutes, or 20% of 45 minutes.
Another way to do that is to simplify the ratio 9:45, which gives me 1:5.
That means that 9 minutes is 1 out of 5 equal parts of 45 minutes.
Either way, I get the same fraction, 0.2 or 1/5.