The common ratio is r = 1/6. We multiply each term by 1/6, which is the same as dividing each term by 6. To find r, divide any term you want over the previous term r = 12/72 = 1/6 r = 2/12 = 1/6 etc.
Now use the infinite sum formula to find S S = infinite sum S = a/(1-r) ... see note below S = 72/(1-1/6) S = 72/(6/6 - 1/6) S = 72/(5/6) S = (72/1) divided by (5/6) S = (72/1)*(6/5) S = (72*6)/(1*5) S = 432/5 S = 86.4
Answer: 86.4
note: this infinite sum formula only works if -1 < r < 1. In the case of r = 1/6 = 0.167 (approx), this r value is between -1 and 1.
Ten percent is 3 starburst because to find ten percent you divide the total number by ten. now to find 70 percent you times ten percent by seven. 3 x7 = 21 :)
