Use a system of equations to solve this problem. Dr. Graham currently has two acid solutions. She only has a 60% acid solution a
nd a 20% acid solution in her lab. Dr. Graham needs 30 L of a 50% acid solution to conduct an experiment. How many liters of each solution should she mix together? Let x = the amount of 60% acid solution
<span>Dr. Graham currently has two acid solutions. 60% acid AND 20% acid </span> Dr. Graham needs 30 L of a 50% acid solution We set up 2 equations in which s = 60% acid and t = 20% acid A) s + t = 30 B) .60s + .20t = (.50 * 30) We multiply equation A by -.20 A) = -.20s -.20t = -6 then we add it to B) B) .60s + .20t = 15 .40s = 9 s = 22.5 t = 7.5 So, she needs to mix 22.5 liters of 60% acid with 7.5 liters of 20% acid.
<span> Let x be the smaller number.
Then 3x is the larger number.
We also know that the smaller added to the larger is 52, or:
x + 3x = 52
4x =52
x = 13
Therefore the smaller is 13, the larger is 3(13)=39. </span>
