3/8 и 15/16=6/16 и 15/16
19/80 и 13/16=19/80 и 65/80
5/9 и 41/81=45/81 и 41/81
11/75 и 14/15=11/75 и 70/75
1/8 и 1/10=5/40 и 4/40
6/25 и 7/40=48/200 и 35/200
5/16 и 1/12=15/48 и 4/48
1/24 и 5/18=3/72 и 20/72
1ч= 10/10
30 мин =5/10=1/2
15 мин=1/4
6 мин= 1/10
AB=x
BC= x-12,71
CD=x+2,85
AB+BC*CD=x+x-12,71+2,85 = 2x-9,86