$25\times10+(25+1)\times7=432$ 
Peter has a rope, and he ties some knots, each using $10$-cm rope. He ties $25$ knots in total. After he ties the last knot, the knots divide the rope into pieces~ equally, and the length of each piece is $7$ cm. What is the length of the entire rope? 
Options:
1. $$425$$ cm 
2. $$432$$ cm 
3. $$456$$ cm 
4. $$478$$ cm 
5. $$480$$ cm 