Your answer is 15 over four z + 12. Using the distributive property, 3/4 • 5z equals 15/4z, which can't be simplified. Then 3/4 of 16 is 12. If you divide 16 by 4 (the denominator) and then multiply by 3 (the numerator) that yields your answer.
 
        
                    
             
        
        
        
The thousands place (1000) is the fourth number to the left of the decimal, so round that one either up or down based on the number just one spot closer to the decimal, in this case, the hundreds place (100).
so we have 32,420
we can ignore the numbers that are going to become zeros as a result of the rounding . .
32,400
let's round 32,XXX either up or down based on the value in the hundreds place. if that value is 5 or greater, than we round up. if it is less than 5, than we round down. 
4 is in the hundreds place, so we round down
32,000 is the answer
        
             
        
        
        
6 centilitre = 60 millilitre
Total liquid consumed = 355ml + 60ml = 415 mlillilitres