How do you calculate the price of a coupon bond from the prices of zero-coupon bonds?

How would you calculate the price from the yields of zero-coupon bonds?

Why could two coupon bonds with the same maturity each have a different yield to maturity?  

APA 6th edition

Minimun 450 words, add citations and references.

BOOK REFERENCE: Vernimmen, P., Quiry, P., Dallocchio, M., Le Fur, Y., & Salvi, A. (2014). Corporate finance: Theory and practice, (4th ed). Chichester, West Sussex UK: John Wiley & Sons