With the same amount of money ($4.20) at $2.80 per pound, Leo could buy 1.5 pounds of strawberries.
If Leo bought 3.5 lbs of strawberries for $4.20, let's find the cost per pound:
Cost per pound = Total cost / Number of pounds
Cost per pound = $4.20 / 3.5 lbs
Cost per pound ≈ $1.20 per pound
Now, if the strawberries cost $2.80 per pound, we can determine how many pounds Leo could buy with the same amount of money by dividing the total amount he has ($4.20) by the cost per pound ($2.80):
Number of pounds = Total cost / Cost per pound
Number of pounds = $4.20 / $2.80 per pound
Number of pounds = 1.5 pounds
Therefore, with the same amount of money ($4.20) at $2.80 per pound, Leo could buy 1.5 pounds of strawberries.