Inequality:
5x - 3 ≤ 28
Answer:
5x - 3 <span>≤ 28
5x </span><span>≤ 31
x </span><span>≤ 31/5 or 6.2 ($6.20)</span>
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:

For this, we need to find the lowest common multiple of 12 and 15....
common multiples of 12 : 12,24,36,48,60
common multiples of 15 : 15,30,45,60
LCM = 60
the caller that will be the first to win both is the 60th caller