Four Friends A, B, C, D Need to cross a bridge

Crack this Puzzle...

Four friends A, B, C, D
Need to cross a bridge..
A maximum of 2 people can cross at a time..
It is night and they have just 1 lamp.
People that cross the bridge must carry the lamp to see the way..
A pair must walk together at the speed of slower person...

Speeds of
A: 1 minute to cross bridge
B: 2 minutes to cross bridge
C: 7 minutes to cross bridge
D: 10 minutes to cross bridge

Now question is... "what is d total minimum time required by all 4 friends to cross the bridge....?

Scratch ur brains... πŸ˜ƒ
Take ur own time. This is tricky

Click here for Answer

First A and B will go. So 2 mins.
Then B will come back. So 2 mins.
Then C and D will Go. So 10 mins.
Then A will come back. So 1 min.
Then A and B will Go. So 2 mins.
Hence in Total 2+2+10+1+2=17 Minutes.