A man invested \(\$150\) in the stock market. During the first week, he lost \(\$45\). During the second week, he tripled his money. How much does he have at the end of the second week?
First, calculate how much he had at the end of the first week: \(\$150 –\$45 =\$105\). Since he tripled his money, it is then necessary to multiply this value by 3: \(\$105 \times 3 = \$315\)