300=30*5*2
200=50*4*1
150=25*2*3
1000=250*1*4
(3 7/15 * 0,25 + 5/6 - 1 2/5) / (5,4 / (3/20 + 0,75)) =
(52/15 * 1/4 + 5/6 - 7/5 ) / (54/10 / (3/20 + 3/4)) =
(13/15 + 5/6 - 7/5) / (54/10 /(3/20 + 15/20)) =
(26/30 + 25/30 - 42/30) / (54/10 / 18/20) =
9/30 / 6 = 1/20
-3/4+8.5(2.1-2.51)=-3/4+8.5*(-0.41)=-3/4-3.485
-0.75-3.485=4,235