I HAVE TWO STUPID QUESTIONS
1. 4 pipes can fill a tank in 70 minutes. How long will the tank fill when 7 pipes are used. Why do we multiply 70 by 4 and divide it by 7 and not the other way round?
ALSO
2. When we do that map and actual thingy and theres the ratio of 1:5000 and the actual value it 1.6 cm and the map is unknown. What do I do?

Question

I HAVE TWO STUPID QUESTIONS
1. 4 pipes can fill a tank in 70 minutes. How long will the tank fill when 7 pipes are used. Why do we multiply 70 by 4 and divide it by 7 and not the other way round?
ALSO 
2. When we do that map and actual thingy and theres the ratio of 1:5000 and the actual value it 1.6 cm and the map is unknown. What do I do?

insa · Answer

The pipes and time are inversely proportional.

anonymous · Answer

What about the other one?

insa · Answer

Im not that sure about it... Sorry

welshfella · Answer

1 : 5000 is the scale of the map
it means the actual distances in the real world are 5000 times the distances on the map

welshfella · Answer

so if the distance is  1.6 on the map then real distance is 5000* 1.6

anonymous · Answer

THANK YOU GUYS

perl · Answer

another way to do this

d= r*t 
4 pipes = r * 70 min
4/70 = r

d/r = t 
7/ (4/70)= t
t = 40