Can somebody please help with this challenging question?

m sweets are shared among Amanda, Beatrice and Christina. Beatrice has h/2 times as many sweets as Christina while Amanda's share is g times of Beatrice's share.

a) express and simplify, in terms of m, g and h, Amanda's share of the sweets.

b) hence, find Amanda's share of the sweets if m=20, g=2 and h=6

Thank you in advance.