me to solve these problems and help me understand how you got the answers 1. Joan has $4,000 invested, partly at 5% and the remainder 3% interest. The total income he received was $168. How much does she have invested in each investment? 2. A saline solution contains 20 gallons of a mixture of alcohol and water which is 40% alcohol by volume. How much of the mixture should be removed and replaced by an equal volume of water so that the resulting mixture will be 25% alcohol by volume? 3. A laborer is paid $18/day for each day he works and loses $3/day for each day he is idle. At the end of 40 days, he nets $531, How many days was he idle