Calib received $50 for his birthday and put it in his piggy bank. each week, he puts 2 more dollars in his bank. the amount of money in dollars d in his bank is given by d = 2w + 50 where w is the number of weeks he has saved 2 dollars. his sister lara him find how much money he will have after 4, 15, 20, and 36 weeks. this table shows her results. what is the rate of change using lara's values for d and w? is this a linear model or non-linear model? w 4 15 20 36 d d = 2w + 50 = 2•4 + 50 = 8 + 50 = 58 d = 2w + 50 = 2•15 + 50 = 30 + 50 = 80 d = 2w + 50 = 2•20 + 50 = 40 + 50 = 90 d = 2w + 50 = 2•36 + 50 = 72 + 50 = 122 the rate of change varies. it is a linear model. the rate of change is . it is a linear model. the rate of change is 2. it is a linear model. the rate of change varies. it is a non-linear model.