Nicholas performs an experiment in which he pulls a marble from a bag. In his experiment, he finds that he is twice as likely to pull a red marble as a blue marble. If Nicholas pulls 10 red marbles, how many blue marbles does he pull?

Nicholas pulls 5 blue marbles from the bag.

Step-by-step explanation:

Since Nicholas performs an experiment in which he pulls a marble from a bag, and in his experiment, he finds that he is twice as likely to pull a red marble as a blue marble, to determine, if Nicholas pulls 10 red marbles, how many blue marbles does he pull, the following calculation must be performed:

10/2 = X

5 = X

Therefore, Nicholas pulls 5 blue marbles from the bag.

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9