Question

Joes annual income has been increasing each year by the same dollar amount. The first year his income was $15,900 and the 6th year his income was $22,400. In which year was his income $38,000.

Answer 1

17th year

Explanation:

his first year is 15,900 and his 6th year is 22,400. that is a 5 year difference, so subtract the two numbers, and divide them by 5 to get the average income he gets each year.

(22,400-15,900)/5=(6,500)/5=1300

so, we have our slope 1,300. the y intercept is 15,900 because his income is the same after having 15,900. so our equation is y=1,300x+15,900

y is total income and x is years

we have our y (38,000) so we plug it in.

38,000=1,300x+15,900

finally we solve and we should get our x.

38,000-15,900=1,300x+15,900-15,900

22,100=1,300x

22,100/1,300=1,300x/1,300

17=x