Track the remaining percentage after each purchase.<br><br>\\(\begin{aligned}<br>\text{After sandwich (25\%)} &: 75\% \text{ remaining}<br>\\<br>\text{Juice: 40\% of 75\%} &= 30\% \text{ of original}<br>\\<br>\text{After juice} &: 75\% - 30\% = 45\% \text{ remaining}<br>\\<br>\text{Cookie: 50\% of 45\%} &= 22.5\% \text{ of original}<br>\\<br>\text{After cookie} &: 45\% - 22.5\% = 22.5\% = \$13.50<br>\\<br>\text{Original} &= \$13.50 \div 0.225 = \$60<br>\end{aligned}\\)<br><br>Final Answer: \$60