Question

initially, there were the same number of blue marbles and red marbles in a bag. John took out 5 blue marbles and then there were twice as many red marbles as blue marbles in the bag. how many red marbles are there in the bag

Answer 1

10 red marbles

Multiply the # of blue marbles by 2 (since there was TWICE as many red marbles), and you have your answer (above)