1. Find the formula for the sum of an arithmetic series:
The sum of an arithmetic series can be found using the formula:
Sum = (n/2) * (first term + last term)
where:
n = number of terms
first term = 2
last term = 2 + 5(n-1) = 5n - 3
2. Set up the inequality:
We want to find the 'n' where the sum exceeds 1000:
(n/2) * (2 + 5n - 3) > 1000
(n/2) * (5n - 1) > 1000
5n^2 - n > 1000
5n^2 - n - 1000 > 0
3. Solve the quadratic inequality:
Use the quadratic formula to find the roots of 5n^2 - n - 1000 = 0
n = [1 ± √(1 + 4 * 5 * 1000)] / (2 * 5)
n ≈ 28.3 or n ≈ -28.2
Since 'n' represents the number of terms, it must be positive.
Therefore, n > 28.3
4. Find the last number Laverne says:
Last term = 5n - 3
Since n > 28.3, the smallest integer value for 'n' is 29.
Last term = 5 * 29 - 3 = 142
Answer:
Laverne says the number 142 that sends Shirley screaming and running.