a boy travels 20 km north, then 15 km south, how far is he from where he started?
20 - 15 = ?
duh, so easy I should have known that, thank you very much
You're very welcome. :-)
To find out how far the boy is from where he started, we need to calculate the net displacement.
The boy first travels 20 km north, which can be represented as +20 km. Then, he travels 15 km south, which can be represented as -15 km.
To find the net displacement, we can add these two values:
+20 km + (-15 km) = 20 km - 15 km = 5 km
The net displacement is 5 km. Therefore, the boy is 5 km away from where he started.