let the total amount of money that Anna and Bill shared be £ x
amount of money Anna received will be £A=2/7x
amount of money Bill received will be £B=5/7x
let the total amount of money that Carl and Donna shared be £ 2x
amount of money received by Carl is £C=3/4(2x)=3/2x
amount of money received by Donna is £D=1/4(2x)=1/2x
the ratio of money received by them altogether will be:A:B:C:D
this is equal to:
2/7x:5/7x:3/2x:1/2x
this can be simplified to:
2/7:5/7:3/2:1/2
this can further be simplified to:
(2/7*14):(5/7*14):(3/2*14):(1/2*14)
hence we shall have:
4:10:21:7