Thread: percent increase over years

Given ‘y’ is the cost of an article. If the cost of the article increases by ‘x%’ every year from 1945 to 1990, then what is the formula for its cost after 45 years?

A. x {1 + (y/100)} ^ 45
B. y {1 + (x/100)} ^ 45
C. y {1 + (45x/100)}

Originally Posted by sfspitfire23

Given ‘y’ is the cost of an article. If the cost of the article increases by ‘x%’ every year from 1945 to 1990, then what is the formula for its cost after 45 years?

A. x {1 + (y/100)} ^ 45
B. y {1 + (x/100)} ^ 45
C. y {1 + (45x/100)}

After 1 year, the cost is y+(x/100)y=y{1+(x/100)}

After the next year, the cost will be y{1+(x/100)}+y{1+(x/100)}(x/100)=y{1+(x/100)}{1+(x/100)}=y{1+(x/100)}^2

After "n" years, the cost will be y{1+(x/100)}^n