Question

A marketing team is conducting a study on the use of smartphones. In a certain metropolitan area, there were $1.8$ million smartphone users at the end of 2015. The marketing team predicts that the number of smartphones users will increase by $25$% each year. If $y$ represents the number of smartphones users in this metropolitan area after $x$ years, then which of the following equations best models the number of smartphone users in this area over time?

• A. $y=1,800,000{\left(1.25\right)}^x$
• B. $y=1,800,000{\left(25\right)}^x$
• C. $y=25x+1,800,000$
• D. $y=1.25x+1,800,000$

Answer 1

The correct option is A $y=1,800,000{\left(1.25\right)}^x$

Given marketing team is conducting a study on the use of smartphones. In a certain metropolitan area, there were $1.81.8$ million smartphone users at the end of $2015$. The marketing team predicts that the number of smartphones users will increase by $25\%$ each year

Then after one year the smart phone user $=1800000(1+\frac{25}{100})$

Then after $x$ year the smart phone users $=$ $1800000(1.25{)}^x$25