Well if you have 60 and she has 120 i will set it out as a sequence week by week
60,67,74,81,88,95,102,109,116,123,130,137,144,151,158,165,172,179,186,193,200,207,214,221,228,235,242,249,256,263,270
120,125,130,135,140,145,150,155,160,165,170,175,180,185,190,195,200,205,210,215,220,225,230,235,240, 245,250,255,260,265,270 
it would take 31 weeks and the total is 270
        
                    
             
        
        
        
Answer: 29
explanation: you add 1 to get 2, you then add 2 to get 4, then 3 to get to 7, then 4 to get to 11, then 5 to get to 16, then 6 to get to 22, then 7 to get to 29