Question

There are 4 women to cross bridge and flashlight.one or two women can cross the bridge with the flash light at a time.those have different walking speeds.the pair must walk at the rate of slower pace woman1:1 minutes woman2:2 minutes woman3:5 minutes woman4:10 minutes then what is the minimum required time to cross the bridgeall the 4 women without throwing flashlight?

Answer 1

1&2 = 2 
2 returning = 2 
5&10 = 10 
1 returning to get 2 back = 1 
1&2 = 2 
time taken = 2+2+10+1+2 = 17 minutes.

Answer 2

17 minutes. 

1&2 = 2 
1 returning = 1 
5&10 = 10 
2 returning to get 1 back = 2 
1&2 = 2 
time taken = 2+1+10+2+2 = 17 minutes. 

OR 

1&2 = 2 
2 returning = 2 
5&10 = 10 
1 returning to get 2 back = 1 
1&2 = 2 
time taken = 2+2+10+1+2 = 17 minutes.