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
The answer would be 21/50. If you have numbers with a few zeros you can cross one of the top amd bottom until you reach the other numbers, if that makes sense. You can changd 420/1000 to 42/100. Then just keep dividing it by a numner that goes evenly into both the numerator and denominator.
Answer:
The answer is C.This country has both a democracy and a theocracy