Barb is making a bead necklace. she strings 1 white bead, then 3 blue beaads, then 1 white bead, and so on. write the numbers for the first eight beads that are white. what is a rule for the pattern.,

the numbers of first 8 beads which are white are 1,5,9,13,17,21,25,29 think of it as an arithmetic progression here the first term will be 1 cause white was first bead then after 3 blue beads another white added soits position is fifth now the difference would come out as 5-1=4 so now position of next white bead could be predicted by nth term formula of an AP which a+(n-1)d here a is first term which in this case is one and d is difference which here is 4 So nth bead position is 1+(n-1)4