Answer:
The teacher will have 5 pints left.
Step-by-step explanation:
One pint has 16 fluid ounces, therefore if the teacher got 18 pints he has a total of:
lake water = 18*16 = 288 fluid ounces
If each student use 4 fluid ounces, and there are 52 students the class will use:
used = 52*4 = 208 fluid ounces
And the remainder will be:
remainder = 288 - 208 = 80 fluid ounces
remainder = 80/16 = 5 pints
The teacher will have 5 pints left.