Environmental Math

The environmental math teaser poses 10 math questions that you must answer.  As you go through, the program will automatically tell you if your answer is correct.  

You will need a calculator, pencil, and possibly paper and an eraser to calculate the answers. It will likely require 10 minutes of undisturbed time to complete this exercise.  If you get one or more incorrect, write down the problem number so that you can quickly access the answer at the end of the demonstration course.

1. You are planning to put a hot tub/Jacuzzi on your third floor deck. If the hot tub itself weighs 300 lbs empty, has a seating capacity for 3-4, and holds 300 gallons of water, how much would you estimate the deck supports must hold?

Cannot make an estimate without further information
If 4 people can be estimated to weigh between 800-1000 lbs, then about 3/4 ton should do it!
Two tons, plus!
One ton is enough.

2. Two waste streams commingle. The first wastestream originates from filter backwash and contains an instantaneous zinc concentration of 0.60 mg/l. The second waste stream originates from process wastewater and has a zinc concentration of 1.4 mg/l. What is the average Zn of the commingled wastestreams?

2.0 mg/l
Cannot be calculated without further information
1.0 mg/l
1.4 mg/l

3. The influent loading TSS to a 1 MGD WWTP is 200 mg/l. What is the influent loading to the WWTP in lbs/day?

1668 lbs/day before rounding
Cannot be calculated without further information
200 lbs/day
100 lbs/day

4. If a methylene chloride solution (80% pure) filled a 55-gallon drum, what would the drum weigh?

The drum's empty weight plus 8.34 x 55
The drum's empty weight plus 8.34 x 55 x the specific gravity of the solution
The drum's empty weight plus 8.34 x 55 x 0.8
The drum's empty weight plus 8.34 x 55 x the specific gravity of the solution x 0.8

5. If you combine the following, what is the result when appropriately rounded: 
    5.1 + 6.34 + 2 = ?

Cannot be calculated without further information
13.44 
13.4 
13

6. If you multiply 49.5 by 1.0, the result when accounting for significant figures and rounding is

49.5
49
50.
Cannot be calculated without further information

7. If you must add 10.3 mls of dechlorination agent to dechlorinate 101 mls of sample, how much dechlorination agent is required to dechlorinate 2910 mls?

28534 mls
2.8 mls
297 mls
300 mls

8. If you must add 5 lbs of chemicals to treat 990 gallons of  wastewater, how much should you add in lbs/minute to treat 22 MGD wastewater?

111,111 lbs/minute
110,000 lbs/minute
77 lbs/minute
Cannot be calculated without further information

9. If you are adding ½ and ¼, what would this equal?  

2/6
2/8
1/8
¾

10. If you are dividing ½ by ¼, what would this equal?

2/6
2/8
2
1/8