John buys 3 different coolers.  The first one is 100 liters.  The second is 50% bigger than that and the third is half the size of the second.  How much total water can they hold?
The second cooler is 100*.5=<<100*.5=50>>50 liters bigger than the first
So it is 100+50=<<100+50=150>>150 liters
The third is 150/2=<<150/2=75>>75 liters
So the total water they can hold is 100+150+75=<<100+150+75=325>>325 liters
#### 325