Question

The number on messages posted each day on an online message board during the first 5 days it was open are listed below 2,350,2,900,3,450,4000,4,550 The number of messages posted each day follows a pattern which expression can be used to determine the number of messages posted on the nth day ? A. 2,350n B. 550(n t 1,800) C. 550n t 1,800 D. 1,800n t 550

Answer 1

C. 550n + 1800

Step-by-step explanation:

The pattern for the first 5 days is 2350, 2900, 3450, 4000, and 4550.

Then, let's see which equation satisfies this pattern.

For 2350n, we get:

If n = 1

2350n = 2350(1) = 2350

If n = 2

2350n = 2350(2) = 4700

Since 4700 and 2900 are distinct, this is not the correct expression

For 550(n + 1800)

If n = 1

550(n + 1800) = 550(1 + 1800) = 550(1801) = 990550

Since it is different from 2350, this is not the correct expression

For 550n + 1800

If n = 1

550n + 1800 = 550(1) + 1800 = 550 + 1800 = 2350

If n = 2

550n + 1800 = 550(2) + 1800 = 1100 + 1800 = 2900

If n = 3

550n + 1800 = 550(3) + 1800 = 1650 + 1800 = 3450

If n = 4

550n + 1800 = 550(4) + 1800 = 2200 + 1800 = 4000

If n = 5

550n + 1800 = 550(5) + 1800 = 2750 + 1800 = 4550

Therefore, the equation 550n + 1800 satisfies the pattern and it is the correct option. So, the answer is

C. 550n + 1800