77 + 83 = 160, multiply that by 14 days, gives you 2,240
The answer in B. For complicated statistics reasons the Central Limit Theorem states that, for sample sizes of above 25 (or 30 depending on the text!), the distribution of sample means is approximately normal regardless of the distribution of the parent distribution
Ray should buy the first one because it has the greater volume by 1,440 square inches.
Tank 1: 20x20x18=7,200
Tank 2: 40x12x12=5,760
7,200-5,760=1,440
The answer is 180 minutes. because you multiply 30 times 0.20 and you get 6. Then you multiply 6 times 30 and get 180 minutes. And 180 minutes in hours is 3 hours.
