What is the sum of the first 10 terms of the geometric sequence 4,2,1?

The numbers 1,2,3,4,5,7,8,12 and 36 have been written on a board.george and peter remove four numbers each.there is one number left .what is this number if the sum of the numbers george remove is 3 times greater than the sum of the number peter removed?

What is the sum of the greatest common prime factor and least common multiple of 32 and 28?

Rio walked 5 steps forward,8 steps backward,9 steps forward,and 3 steps backward.how many steps is rio from where he started? show the solution(number line)