Okay so i understand none of this. can someone explain how to do this to me?

in one hand you hold a 0.12 kg apple, in the other hand a 0.20 kg orange. the apple and orange are separated by 0.75 m.

a. what is the force of gravity that the orange exerts on the apple.
b. what is the force of gravity that the apple exerts on the orange.

According to newtons 3rd law, every force has an equal and opposite force, which means that the answers for a and b should be the same.
you might be knowing the equation of F which is 

F = G(m1)(m2)/(r^2) ( this formula may be wrong, look it up on google)
G is the universal gravitation constant, just google for the exact value, the value should be something like 6.67E-11
m1 is the mass of an apple
m2 is the mass of an orange
r is the distance between them ( should be squared)