Answer:
7 days
Step-by-step explanation:
At 25% per day, it will take approximately 3 days to double the population, so approximately 6 days for the population to quadruple. Checking that number, we find it is not quite enough for the experiment, so another day is required.
"Guess and check" as a method of solution works especially well if you have an automated checker to evaluate your guess. A graphing calculator or spreadsheet can work well for this.
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We guess 3 days as the doubling time using the "rule of 72" that says the product of percentage and doubling time is about 72. That is, 72/25 ≈ 3. (This is only a very rough approximation of doubling time, best for rates near 8%.)
Answer:
150
Step-by-step explanation:
360 - (130 + 80) = 150
Answer:
The answer is $61.20
Step-by-step explanation:
First you multiply 72 by .15 (which is 15% converted to a decimal), which gives you 10.8. You then subtract 10.8 from 72.
Answer:
Step-by-step explanation:
She added 3x and -2x, getting 5x, instead of x. She needs to pay more attention to the positive/negative signs.
1,000= 3x+x. 1,000=4x. 250=x. 1,000= 3(250) +250. 1,000=750+250. The bench costs $250.