If you can solve 20 multiplication facts in one minute then you could solve 50 multiplication facts in 3 minutes
1 minute = 20 facts
2 minutes = 40 facts
3 minutes = 60 facts
We can check our work by doing the unit rate:
60 facts ÷ 3
____________ <--- fraction bar
3 minutes ÷ 3
= 20 facts
__________ (20 facts per minute)
1 minute