A chemist mixes different solutions. By weight, she mixes 30% of a sample of substitute A and 60% of a sample of substitute B to create substitute C. If she initially had 90 grams of substitute A and 120 grams of substitute B, then what would be the weight, in grams, of substitute C?

You need a 50% alcohol solution. On hand, you have a 500 mL of a 95% alcohol mixture. How much pure water will you need to add to obtain the desired solution?

Mr. and Mrs. Wagner are getting ready to drive across the US from Philadelphia, PA to Los Angeles, CA over five (5) days. The TOTAL distance is approximately 3,000 miles. The average price of gasoline is $4.10 per gallon. They plan to stay in a hotel four (4) nights. They are budgeting $50 per day per person to cover the cost of three (3) meals per day each.    If their van averages 25 mpg, estimate how many gallons of gasoline are needed for the trip. Select the correct answer below.