I need help with my aviation ignment?

u can add this..hiby p ratio 75% air goes around the core rest 25% taken in to the core of the engine.80% thrust comes from the turbine fan and rest from the core.r/r uses 3 spool and pw used dual spool......long duct used by the r/r is qiueter comparing to the short duct engine. in the long duct the hot air from thr core and the cold air tsreem mixes in the long exhaust duct which is also well isulated ..before released to the atmosphere..this make the enginr quieter.. the sound is suppressed in the duct before exit....the short ductm is lighter but the hot air and cold air streem meet out side and the energy exchange and the friction produces some noise ....anyway 757 production is stopped to make way to the jet liner 787..