linear growth word problem

Question

Paul opens a savings account with $350. He saves $150 per month. Assume that he does not withdraw money or make any additional deposits. Classify the model and write the corresponding function. Determine how much money he will have after 7 months After how many months will he have $2000?

Answer 1

The problem can be simply expressed as a linear equation:  

 

Total = $350 + $150*M   (350 is the initial deposit, and M = months)

 

After 7 months (or M=7)  

Total = 350 + 150*7    or  

Total = 350 + 1,050     = $1,400

 

(part 2)  If we know the total, we then just solve for M.

 

Total = $2,000 = $350 + $150*M    or  (subt 350 from each side)

           $1,650 = $150*M    or  

                   M = 1,650/150 = 11 months