Question 1207292
a = number of liters of paint A.
b = number of liters of paint B.
c = number of liters of paint C.


you have a + b + c = 360.


a/b = 3/2.
cross multiply to get 2a = 3b


b/c = 1/2.
cross multiply to get 2b = c.


solve in terms of b for all ratios.
2a = 3b gets you a = 3b/2.
c = 2b gets you c = 2b.


a + b + c = 360 becomes 3b/2 + b + 2b = 360 after replacing a and c with their equivalent values in terms of b.
multiply both sides of that equation by 2 to get 3b + 2b + 4b = 720
combine like terms to get 9b = 720.
solve for b to get b = 720 / 9 = 80.


you have a = 3b/2 = 3*80/2 = 120.
b = 80.
c = 2b = 2*80 = 160.


a = 120, b = 80, c = 160.
a + b + c = 120 + 80 + 160 = 360.


A is 1800 per liter.
B is 2400 per liter.
C is 1275 per liter.


total price is 120 * 1800 + 80 * 2400 + 160 * 1275 = 612000.
612000 / 360 = 1700 per liter.


that's your solution.
1 liter of the mix would cost 1700.