David found a new part-time job that pays $2400/month. This is 5 times what he made at his previous job. What was David’s yearly salary at his old job?
Let x be David's monthly salary at his old job.
His new salary is 5*x=2400.
So his old salary was x=2400/5=<<2400/5=480>>480 dollars.
So his yearly salary was 480*12=<<480*12=5760>>5760 dollars. Answer: \boxed{5760}.
To find David's yearly salary at his old job, we need to determine how much he was making per month at his old job. We know that at his new job, he earns $2400 per month, which is 5 times what he made before.
Let's say David's monthly salary at his old job was x.
According to the given information, 5 times his old monthly salary equals $2400.
So, we can write the equation:
5x = $2400
To solve for x, we need to isolate it.
Dividing both sides of the equation by 5:
(5/5)x = $2400/5
x = $480
Therefore, David's monthly salary at his old job was $480.
To determine his yearly salary at his old job, we need to multiply his monthly salary by 12 (the number of months in a year):
Yearly salary at his old job = $480/month * 12 months/year
= $5760/year
So, David’s yearly salary at his old job was $5760.