All Tables in Dining Room-
Make the given numbers into a fraction- 10/8 (minutes/tables).
10/8 ÷ 2/2 = 5/4
5/4 ÷ 2/2 = 2.5/2 (that is 2.5 minutes to set up two tables)
2.5/2 × 15/15 = 37.5/30
It will take a waiter 37.5 minutes to set up all 30 tables.
16 Tables-
10/8 (minutes/tables)
10/8 × 2/2 = 20/16
It will take 20 minutes to set up 16 tables.