A rectangular field with sides as shown below has to be fenced all around. If fencing posts have to be fixed at 1-metre intervals, how many posts are needed?
1. 167
2. 334
3. 668
4. 6840
![A rectangular field with sides as shown below has to be fenced all around If fencing posts have to be fixed at 1metre intervals how many posts are needed1 1672 class=](https://us-static.z-dn.net/files/d1d/1691d78799db4d6a3f028ad83f37e3a2.jpg)