Answer:
I am pretty sure its 30 students
Would it be y = 18t + 18r?
Answer:
89
Step-by-step explanation:He bought 89 items because 20 + 3 is 23, 23 + 12 is 35, 35 + 11 is 46, 46 + 24 is 70, and 70 + 11 is 89.
Answer:
Part 1: There are 4.7*10^21 ways to select 40 volunteers in subgroups of 10
Part 2: The research board can be chosen in 32760 ways
Step-by-step explanation:
Part 1:
The number of ways in which we can organized n elements into k groups with size n1, n2,...nk is calculate as:

So, in this case we can form 4 subgroups with 10 participants each one, replacing the values of:
- n by 40 participants
- k by 4 groups
- n1, n2, n3 and n4 by 10 participants of every subgroups
We get:

Part 2:
The number of ways in which we can choose k element for a group of n elements and the order in which they are chose matters is calculate with permutation as:

So in this case there are 4 offices in the research board, those are director, assistant director, quality control analyst and correspondent. Additionally this 4 offices are going to choose from a group of 5 doctors.
Therefore, replacing values of:
- n by 15 doctors
- k by 4 offices
We get:

Answer:
The coordinates of the mid-point of JL are (-5 , 2)
Step-by-step explanation:
If point (x , y) is the mid-point of a segment whose end-points are
and
, then
and 
∵ JL is a segment
∵ The coordinates of J are (-6 , 1)
∴
= -6 and
= 1
∵ The coordinates of L are (-4 , 3)
∴
= -4 and
= 3
Lets use the rule above to find the mid-point of JL
∵ 
∴ x = -5
∴ The x-coordinate of the mid-point is -5
∵ 
∴ y = 2
∴ The y-coordinate of the mid-point is 2
∴ The coordinates of the mid-point of JL are (-5 , 2)