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: x ≤ 15
Step-by-step explanation: All we need to do is divide both sides by 1/3, so1/3x / 1/3 and 5/ 1/3 = 15. So x ≤ 15.
Hope this helps!
The answer would be letter B
For the right triangle to be given in name of three letters such as this, the right angle is most likely to be in the center, in this case letter K. To determine the common trigonometric properties of a certain angle we may use of the mnemonics SOH - CAH - TOA.
sin angle = opposite side / hypotenuse
cosine angle = adjacent side / hypotenuse
tangent angle = opposite side / adjacent side
If we let small letter j, k, and l be the sides opposite to angles J, K, and L, respectively. Then, the cos (L) will be,
cos (L) = j/k