Nkc tf BD
Mcd fb
Mab tB
Nk Ac
Kc AD
Ma ek
Bt
Mc aB
Cd Bc
Ba cD
Kd ef
Ka fk
AD
Система
a1 + 4d = 9
a1 + d + a1 + 8d = 20
a1 + 4d = 9
2a1 + 9d = 20
a1 = 9 - 4d
2(9 - 4d) + 9d - 20 = 0 *
a1 = 9 - 4d
d = 2
a1 = 1
d = 2
S10 = (a1 + a10)*5 = (1 + 19)*2 = 40
Ответ
40
(7/6-1/12+1/36)*72/34
((7*6)/36 - 3/36 +1/36)*72/34
40/36 * 72/34
20/1 * 2/17
40/17
2 6/17
.............................
7 * 285 : 133 = 15 канистр понадобится