Answer:
39
Step-by-step explanation:
To find the intervals you will need to find the lowest and highest numbers, in this case, it would be 1 and 35. A general rule would be 5-7 intervals, I will use 5.
Here are the intervals with the number of people that were in each:
1-7 (9)
8-14 (14)
15-21 (8)
22-28 (3)
29-35 (5)
14+9+8+3+5=39
2 for 3
8÷6=$1.33
10÷10=$1.00
2÷3=$0.66
.80
2 for $3 is less than the rest therefore it is a better deal
14.29% increase
Hope this helps!