13 7/12=163/12
12 3/16=195/16
19 23/24=479/24
НОК(12; 16; 24)=48
163/12=163×4/12×4=652/48
195/16=195×3/16×3=585/48
479/24=479×2/24×2=958/48
1) 958/48-652/48=306/48 - третий арбуз;
2) 585/48-306/48=279/48 - второй арбуз;
3) 652/48-279/48=373/48 - первый арбуз.