Question 1124565
Andrew got x
Bobby got 1.5 x
700-2.5 x remained
They were shared 3:2 
That means Jeff had 420-1.5x and Simon 280-x, both of those being in a 3:2 ratio (dividing each by 5 and multiplying by 3 and 2 respectively.)
But Simon's 280-x is 0.4*x
So 280-x=0.4x
1.4x=280
x=200 for Andrew
Bobby got 300
200 remained, which is 700-500, and 500 is 2.5x
Jeff had 420-300 or 120 marbles
Simon had 80 marbles

Bobby and Jeff together got 420 marbles ANSWER