Answer:
15 days
Explanation:
it she can crochet 1/15 of a blanket in a day, that means it will take her 15 days to make 1 blanket. As she is making 3 blankets she will need 3x the amount
3 x 15 = 45 (this is how long it will take her to make 3 blankets)
60 - 45 = 15 (this is the amount of days she doesn't need to crochet)
I hope this helped:-)