<u>Answer:</u>
1 cm : 10.5 km
<u>Step-by-step explanation:</u>
We are given that two towns are 31.5 km in real and are 3 cm apart on a map and we are to find the scale of the map.
For this, we can use the ratio method.



Therefore, the scale of the map would be 1 cm : 10.5 km.
You could say 84/2, 126/3, or even 168/4
Answer:
10 mph
Step-by-step explanation:
speed of boat in still water = x
speed of current = 5
speed of boat with current (downstream) = x + 5
speed of boat against current (upstream) = x - 5
distance downstream = 9
distance upstream = 3
time = t
speed = distance/time
distance = speed × time
downstream:
9 = (x + 5)t
upstream:
3 = (x - 5)t
9 = xt + 5t
3 = xt - 5t
9 = xt + 5t
-3 = -xt + 5t
-----------------
6 = 10t
t = 0.6
9 = (x + 5)0.6
15 = x + 5
x = 10