Work backwards from the file cost. The file ($4) is 2/5 of the remainder after food; that remainder is 2/3 of the total.<br><br>[[model:questions/solutions/q4339.png]]<br><br>• File = $4 = 2/5 of remainder after food<br>• 1/5 of remainder → $4 ÷ 2 = $2<br>• Remainder after food → $2 × 5 = $10<br>• Remainder = 2/3 of total → 1/3 = $5, total = $15<br>• Food → 1/3 × $15 = $5<br>• Money left → $15 − $5 − $4 = $6<br><br>Mandy had $6 left.<br>Check: Food $5 + File $4 + Left $6 = $15 total. ✓