Answer:
540
Step-by-step explanation:
Amount of antifreeze in the 90% solution + amount of antifreeze in the 20% solution = amount of antifreeze in the 80% solution
0.90 x + 0.20 (90) = 0.80 (x + 90)
0.90 x + 18 = 0.80 x + 72
0.10 x = 54
x = 540
You need 540 gallons of 90% antifreeze solution.
Answer: 
Step-by-step explanation:
Given
The total no of beads is 52
there 13-red,13-blue,13-green, and 13-black
favorable outcomes to select a blue bead is 13
Total outcomes are 52
Probability is given by

30÷5=6
4×5=20
for every 30 green lights there are 20 white lights
The answer to 4 1/5 divided by 2 4/5 is 3/2
3 cards
1/4 = x/12 1/4 = 3/12
4 * 3 = 12
1 * 3 = 3
x = 3