What is the estimate 20 9/11 divided by 6 19/20?
A) 147
B) 120
C) 4
D) 3

Sorry guys but as you have a small brain

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.

Define multiplicative inverse. give an example of a number and its multiplicative inverse.