At the start of the game, Peter and Jack had 48 marbles altogether. In the first round, Peter lost 2/5 of his marbles to Jack. In the second round, Jack lost 1/9 of his marbles to Peter. At the end of the second round, they had the same number of marbles. How many marbles did Jack have at first?
+37153 p+j = 48 p = 48- j
(j + 2/5 p) 8/9 = 24
(j + 2/5 ( 48-j) ) 8/9 = 24
j = 13
