Answer: 
Step-by-step explanation:
Here, According to the question, The population of the world is 4 billion (approx).
Again According to the question, The world's population has grown at an average rate of 1.9 percent per year since 1945.
Therefore, after 1975 the growth rate will remains same.
Thus, the population of the world after t years,
(By the formula
)
⇒
Where 1.019 is the growth rate and 4 billion is the initial population.
Missing part of the question
Determine the number of handshakes, i, that will occur for each number of people, n, in a particular room. (people)
Answer:

Step-by-step explanation:
Given
For 5 people

Using the given instance of 5 people, the number of handshakes can be represented as:

The above sequence is an arithmetic sequence and the total number of handshakes is the sum of n terms of the sequence.

Where
--- The first term
--- The last term
So:


Answer:
C
Step-by-step explanation:
Answer:
1,000.
Step-by-step explanation:
Check the picture below.
the lateral area, namely the area of the sides, as you see in the picture, is really just the area of 6 rectangles.
front and back, two rectangles of 5x25,
left and right, two rectangles of 2x25.
simply get the area of each and sum them up, that's the lateral area of the prism.