Mixture and Work Problems

How many liters of acid must be added to 10 liters of a 20% acid solution to make a 50% acid solution?

(a)  

How do you solve Mixture problems?

How many mL of water must be added 500 mL of a 40% alcohol solution to reduce it to a 25% alcohol solution?

(a)  

How many pounds of water must be evaporated from 50 lbs. of a 3% salt solution so that the remaining solution will be 5% salt?

(a)  

One alloy contains 80% gold and another alloy contains 55% gold. The two alloys are combined to make 50 grams of an alloy that is 70% gold. How many grams of the 80% alloy are used?

• 32 g

• 24 g

• 26 g

• 40 g

Cruz emptied 20% of a 5-liter container of anti-freeze solution with a 60% concentration of anti-freeze. How many L of pure water must he add so that the new solution will have 50% concentration of antifreeze?

• $\frac{24}{5}\ L$

• $\frac{6}{5}\ L$

• $\frac{2}{5}\ L$

• $\frac{4}{5}\ L$

How did you do? Are you feeling refreshed?

• I did great, but I am dying inside

• I did great, wow i'm so confident i'll ace the test

• I didn't do well, Hey! where are the power ups when you need them?!

• I am just dying inside

• I don't know what to feel anymore

How do you solve a work problem?

Brooklyn can do a particular typing job in 6 hrs. while Victoria can do the same job in 4 hrs. If they work together, how many hours will it take them to finish the job?

(a)  

Bella can do a piece of work in 10 days. After she has worked for 2 days, Edward comes and joins her and together finish the work in 3 more days. In how many days could Edward have done the work by himself?

• 6

• 12

• 5

• 8