One canned juice drink is 25% orange juice ; another is 10% orange juice. how many liters of each should be mixed towing order to get 15l that is 13% orange juice?

Assumptions

Let x be the amount of 25% orange juice
Let y be the amount of 10% orange juice


There are 15 litres of 13% orange juice

x + y = 15


The 15 litres of juice is 13% orange juice

0.25x + 0.1y = 15 x 0.13
0.25x + 0.1y = 1.95


Rewrite the equations and solve for x and y

x + y = 15 (Equation 1)
0.25x + 0.1y = 1.95 (Equation 2)

(Equation 1):
x + y = 15
x = 15 - y  (Substitute into Equation 2)

0.25 (15 - y) + 0.1y = 1.95
3.75 - 0.25y + 0.1y = 1.95
0.15y  = 1.8 
y = 18 ÷ 0.15
y = 12 (substitute into Equation 1)

x + y = 15
x + 12  = 15
x = 15 - 12
x = 3

x = 3 and y = 12


3 liters of 25% of orange juice with 12 liters of 10% orange juice