This is simple algebra :)
First, we can write the question as an algebraic equation.
Given that Doug spent 40 more hours than Laura, we can represent Laura as (x) and Doug as (x+40).
"Doug and Laura spent a combined 250 hours." So we can write this as
(x) + (x+40) = 250
Now simplify:
2x + 40 = 250
Solve x by subtracting 40 from both sides of the equation:
2x = 210
Therefore:
x = 210/2
= 105
So Laura (x) spent 105 hours!
4>-4, as -4 is less than 0 and 4 is greater than 0.
A _______ is a commonly accepted set of scientific ideas and assumptions.
Answer: paradigm
Here's a pattern to consider:
1+100=101
2+99=101
3+98=101
4+97=101
5+96=101
.....
This question relates to the discovery of Gauss, a mathematician. He found out that if you split 100 from 1-50 and 51-100, you could add them from each end to get a sum of 101. As there are 50 sets of addition, then the total is 50×101=5050
So, the sum of the first 100 positive integers is 5050.
Quick note
We can use a formula to find out the sum of an arithmetic series:

Where s is the sum of the series and n is the number of terms in the series. It works for the above problem.
Answer:
5
Step-by-step explanation:
2x5x7=70