Answer:
60.5% was the amount the zebra drank
Step-by-step explanation:
The bottle in total is 15+23=38 units
To get the % for the zebras portion you divide 23 by 38 which equals roughly 0.605 or 60.5%
edit: 1/5 of 100% is 20% which leaves 80%, 2/3 of the 80% thats left is 53.3333%
so you divide 1 by 5 which equals 0.2 or 20%, which leave 80%, then you divide 2 by 3, which equals 66.6666%, times that by the 80% (0.80 x 0.666666) equals 0.533333 or 53.333%
Therefore the Zebra drank 53.333% of the bottle