The LCM is the smallest common multiple. To find this, list the multiples of each number
52: 52, 104, 156....
13: 13, 26, 39, 52.....
the smallest number that is a mutiple of both is 52.
so, the LCM of 13 and 52 is 52.
Hope this helps!
Answer:

Step-by-step explanation:
Sum the frequency column to find the total number of students
total = 2 + 9 + 5 + 5 + 3 = 24
number of students finished in less than 20 mins = 2 + 9 + 5 = 16
fraction of students =
= 
You need to use the Law of Cosines:
AC² = AB² + BC² - 2·AB·BC·cos(b)
Therefore, you get:
AC = √(90² + 80² - 2·90·80·cos(50)
=√5243.86
= 72.4 in
Now you can sum up all the sides in order to find the perimeter:
AB + BC + AC = 90 + 80 + 72.4 = 242.4 in
The correct answer is A) 242.4 in
The answer is 5 months, with the cost of $85. You can find this answer by first writing the charges as 12x + 25 and 10x + 35. Then, you set them equal to each other and solve to find x, which is the number of months.
12x + 25 = 10x + 35
- 10x
2x + 25 = 35
- 25
2x = 10
÷ 2
x = 5
Now that we know what x is, we can substitute it in and get 10(5) + 35 = 50 + 35 = 85.
I hope this helps!