A compound gear train is composed of four gears, A, B, C, and D. Gear A has 10 teeth and is meshed with gear B. Gear B has 20 teeth and shares a shaft with gear C, which has 16 teeth. Gear C is meshed with gear D, the output gear. Power is supplied at gear A with 100ft•lb of torque and is traveling at 1600rpm.

Q (2)
The necessary torque output for the system is 500ft•lb. What should the gear ratio of the system be?

Q (3)
With a system torque output of 500ft•lb, how many teeth should gear D have?
"I need help finding the formula to this I suck at this type of work and need help!

Question

A compound gear train is composed of four gears, A, B, C, and D. Gear A has 10 teeth and is meshed with gear B. Gear B has 20 teeth and shares a shaft with gear C, which has 16 teeth. Gear C is meshed with gear D, the output gear. Power is supplied at gear A with 100ft•lb of torque and is traveling at 1600rpm.

Q (2) 
The necessary torque output for the system is 500ft•lb. What should the gear ratio of the system be?

Q (3) 
With a system torque output of 500ft•lb, how many teeth should gear D have?
"I need help finding the formula to this I suck at this type of work and need help!