###Human: Each week Carina puts 20 more seashells in a jar than she did the week before. If there are 50 seashells in the jar this week, how many will there be in a month?, ### Assistant: In one week there will be 50+20=70 seashells
In two weeks there will be 70+20=90 seashells
In three weeks there will be 90+20=110 seashells
In four weeks there will be 110+20=130 seashells 
 So the answer is :  130