The contamination level at P20 was recorded as medium.
To determine which statement must be true, let's analyze the given conditions:
Pump | Contamination Level |
---|---|
P1 - P5 | 3 High |
P6 | Low |
P7-P8 | Same Level |
P16-P20 | No High |
Let's consider:
We need to accommodate the constraints, especially that P6 is the only low among P1-P10, and P16-P20 can't be high:
Conclusion: Given this breakdown, The contamination level at P10 was recorded as high must be true. It fits all conditions without contradiction.
At least 8
At most 9
To solve the problem, we need to determine the number of pumps at which contamination levels were recorded as medium. Let's use the given information to deduce the number of pumps with each contamination level:
There are 20 pumps in total: P1 to P20.
From statement 1, three of the pumps (P1-P5) have high contamination.
From statement 2, P6 is the only pump from P1 to P10 with low contamination, leaving the rest with either high or medium contamination.
Statement 3 indicates P7 and P8 have the same contamination level; since P6 is low and not adjacent to P7 and P8, these two must be either high or medium. Based on statement 1, neither can be high, so both must be medium.
Statement 4 says no high contamination at P16-P20.
Statement 5 states that high contamination pumps are twice the number of low contamination pumps. Therefore, let x be the number of low contamination pumps. Then, there are 2x high contamination pumps. Only one low contamination pump is given (P6), so x=1, making high contamination pumps 2x=2.
Based on the information:
High contamination pumps: 2 from P1-P5 and undistributed elsewhere due to limitation at P16-P20.
Low contamination pump: P6.
From the calculation above, we have identified the following contamination distribution: 2 high, 1 low (P6), and two medium (P7 and P8). Therefore, the remaining ambiguity should be calculated: Medium contamination pumps = Total pumps - High pumps - Low pumps = 20 - 6 - 2 = 8 medium contamination pumps.
Thus, the number of pumps at which contamination levels were recorded as medium is exactly 8.
To determine which statement must be true if the contamination level at P11 was recorded as low, we will analyze the given conditions one by one:
Assuming P11 has a low contamination level, let's examine how this affects the rest, especially P14:
Hence, the statement that must be true is:
The contamination level at P14 was recorded as medium.
Contamination levels at P10 and P14 were recorded as the same.
To solve this problem, we must determine which statement MUST be FALSE given that the contamination level at P15 is recorded as medium.
The constraints given are:
Let's examine the options:
Thus, the only statement that cannot be true is the contamination levels at P11 and P16 were recorded as the same.