On the map ,
1cm=5km
therefore , 4.7cm= 5/1 x 4.7
=23.5 km <--------------answer
Let:
v = Olga's speed
t = the time Anna spent going to school (3 km/hour)
t/2 = the time Anna spent running back home with speed of 6 km/hour
So, t + t/2 = 3t/2 is the total time
In the meantime distance = speed*time and the both made the same distance we can put it as:
3t + 6*(t/2) = (3t/2)*v
6t = (3/2)tv divide both sides by t
(3/2)v = 6
v = 2*6/3
v = 4 km/hour
Olga's speed was 4 km/hour.
N = -3
5n + n + 6 = -18 - 2n
6n + 6 = -18 - 2n
-6 to both sides
6n = -24 - 2n
+2n to both sides
8n = -24
divide 8 to both sides
n = -3