Call the rate in still water vs;
upstream you have: vs-v=6/4
downstram you have: vs+v=6/3
where v is the rate with which the river flows.
rearranging:
vs-v=3/2
vs+v=2
from the second you have v=2-vs substitute into the first:
vs-2+vs=3/2
2vs=7/2
vs=7 mi/hr
2 | 3
45| 67.5
33| 50
multiplying and dividing by 1.5 based off of the 2-3 ratio.
18/12=22.50/n
he could buy 15 gallons
Im pretty sure she has 6 quarters and 12 nickels since it it twice as much.
$0.25 x 6 =150
$0.5 x 12 =60
total = 210