Work from Wong's salary to find Lee's, then Tan's, then the difference.<br><br>&bull; Lee = 85% of Wong = \(\$4000 \times 0.85 = \$3400\)<br>&bull; Tan = 120% of Lee = \(\$3400 \times 1.20 = \$4080\)<br>&bull; Difference = \(\$4080 - \$3400 = \$680\)<br><br>Final Answer: \(\$680\)