Use units to find the amount of each juice remaining, then solve using the given difference.
[[model:questions/solutions/q10436.png]]
Let orange juice = \(5u\) and apple juice = \(3u\).
• After 20% of orange juice was drunk: orange remaining = 80% of \(5u = 4u\).
• After 50% of apple juice was drunk: apple remaining = 50% of \(3u = 1.5u\).
• Difference in what remains = \(4u - 1.5u = 2.5u = 90\) ml.
• \(u = 90 \div 2.5 = 36\).
• Total juice at first = \(5u + 3u = 8u = 8 \times 36 = 288\) ml.
The container had 288 ml of juice at first.
Check: Orange = 180 ml (left 144 ml), Apple = 108 ml (left 54 ml). 144 − 54 = 90. ✓