Answer:
24 oz has the lowest cost per ounce.
Step-by-step explanation:
12 oz ---> $2.49
1 oz --> $2.49/12
1 oz --> $0.2075
14 oz --> $3.15
1 oz --> $3.15/14
1 oz --> $0.225
20 oz --> $5
1 oz --> $5/20
1 oz --> $0.25
24 oz --> $4.56
1 oz --> $4.56/24
1 oz --> $0.19 ..........this is the lowest cost per ounce
36 oz --> $7.2
1 oz --> $7.2/36
1 oz --> $0.2
R = speed in still water
r + c = speed with current
r - c = speed against current
3.5(r + c) = 70
r + c = 20
c = 20 - r
4(r + c) = distance from pier to pier
5(r - c) = distance from pier to pier
4(r + c) = 5(r - c)
4(r + 20 - r) = 5(r - 20 + r)
80 = 10r - 100
180 = 10r
18 = r
The speed in still water is 18 km/hour
841 rounded to the nearest 10th is 840...hope this helps u :)
