Answer:
70
Step-by-step explanation:
21/.3
Although the number of new wildflowers is decreasing, the total number of flowers is increasing every year (assuming flowers aren't dying or otherwise being removed). Every year, 25% of the number of new flowers from the previous year are added.
The sigma notation would be:
∑ (from n=1 to ∞) 4800 * (1/4)ⁿ , where n is the year.
Remember that this notation should give us the sum of all new flowers from year 1 to infinite, and the values of new flowers for each year should match those given in the table for years 1, 2, and 3
This means the total number of flowers equals:
Year 1: 4800 * 1/4 = 1200 ]
+
Year 2: 4800 * (1/4)² = 300
+
Year 3: 4800 * (1/4)³ = 75
+
Year 4: 4800 * (1/4)⁴ = 18.75 = ~19 (we can't have a part of a flower)
+
Year 5: 4800 * (1/4)⁵ = 4.68 = ~ 5
+
Year 6: 4800 * (1/4)⁶ = 1.17 = ~1
And so on. As you can see, it in the years that follow the number of flowers added approaches zero. Thus, we can approximate the infinite sum of new flowers using just Years 1-6:
1200 + 300 + 75 + 19 + 5 + 1 = 1,600
Answer:
Step-by-step explanation:
I'm not sure my way is going to be any quicker or better. Let's take an example.
Suppose you start with 456
Put a decimal at the end of the 6. You get 456.
Shift the decimal to the left one place 45.6
Divide by 2
22.8 (done mentally)
Note: dividing by 2 is easier than dividing by 5. Or multiplying by 5 for that matter.
Check the result.
456 * 5/100 =2280 / 100.
Shift a decimal 2 places to the left.
22.80 which agrees with your result.
Answer:
Step-by-step explanation:
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