Bruce has $150 and saves $20 each week. Katie has $200 and saves $10 each week. after how many weeks will they have the same amount of money? how much money will they have at the time?

so to solve this problem just add bruce's saved money ($150) to the $20 he saves each week. do the same with katie.
               bruce                            katie   
  week 1  150+20=170       week 1  200+10=210                    
week 2  170+20=190                              
week 3  190+20=210                        so in 3 weeks bruce will have the same                                                             number of money as katie in week 1