There were 75 marbles in boxes a,b&c.after moving 28 marbles from box a to b,24 marbles from b to c &19 marbles from c to a,there was an equal number of marbles in each box.how many marbles were there in each box a at first?
a+b+c = 75
a-28+19 = b+28-24 = c+24-19
or
a+b+c = 75
a-9 = b+4
a-9 = c+5