X = amount of 50% solution
y = total amount after mixing
Note that the amount of alcohol in the 20% solution is 80 (0.2) = 16 oz.
We have 2 unknowns, so we need 2 equations:
first, we can write the equation for the total volume:
y = x + 80
next, apply the percentages to get an equation for the amount of alcohol:
0.4 y = 0.5 x + 16
Finally, solve the pair of equations (in this case, by substitution of the 1st into the second:
0.4 (x + 80) = 0.5x + 16
0.4 x + 32 = 0.5X + 16
rearrange and combine like terms:
0.1x = 16
x = 160
from the 1st equation:
y = 160 + 80 = 240
1 1/2
because 1 1/2 equals 1 3/6. so 1 3/6 is bigger than 1 1/6.
Answer:

Step-by-step explanation:

Answer:
a. 14 b. -2
Step-by-step explanation:
a. 10=2x-18
28=2x ; x=14
b. 3x+12=2x+6+4
3x+12=2x+10
x=-2