Question

What is the average of all numbers between 2000 and 2400 that are divisible by 50?

• A. 2200
• B. 2175
• C. 2250
• D. 2300

Answer 1

Answer:

A. 2200

The numbers divisible by 50 between 2000 and 2400 (inclusive) are:

2000, 2050, 2100, 2150, 2200, 2250, 2300, 2350, 2400

These form an arithmetic sequence.

The average of an arithmetic sequence is:

$\frac{\text{First term}+\text{Last term}}{2}$

$=\frac{2000+2400}{2}$
$=\frac{4400}{2}$
$=2200$