Answer:
Step-by-step explanation:
you
60 +14*number of weeks
sister
120+10*number of weeks
let x be the number of weeks until they have the same amount of money
60+14x = 120+10x ; isolate like terms
14x -10x = 120-60
4x = 60; divide both sides by 4
x= 15 weeks
120+10*15 = 120+ 150 = $270 will be the amount they will have the same