Answer:
<em>It took 31 days for the patch to cover half the lake</em>
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Step-by-step explanation:
The patch grows to double its size everyday
the patch completely covers the lake in 32 days
Since the patch doubles itself everyday, this means that the previous day before the 32nd day, the lake was just half covered.
Therefore, the the patch covered half the lake on the 31st day, i.e <em>it took 31 days for the patch to cover half the lake</em>
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Answer:
-4.01, -4, -7
Step-by-step explanation:
equation:
-x + 6 ≥ 10
substitute each number for x
- (-3.9) + 6 ≥ 10 = (negatives cancel each other out) 3.9 + 6 = 9.9 ≥ 10 (incorrect)
-4 + 6 ≥ 10 = 2 ≥ 10 (incorrect)
- (-4.01) + 6 ≥ 10 = (negatives cancel each other out) 10.01 ≥ 10 (correct)
- (-4) + 6 ≥ 10 = (negatives cancel each other out) 10 ≥ 10 (correct)
-4.01 + 6 ≥ = 1.99 ≥ 10 (incorrect)
-3.9 + 6 ≥ 10 = 2.1 ≥ 10 (incorrect)
-0 + 6 ≥ 10 = 6 ≥ 10 (incorrect)
- (-7) + 6 ≥ 10 = (negatives cancel each other out) 11 ≥ 10 (correct)
For the first digit there are 7 choices. For the second digit there are 6 choices (because we can't use the same one again). And so on, until there is only one choice for the last digit.
The number of possible codes is this:
7*6*5*4*3*2*1 = 7! = 5040