Abag contains blue marbles and red marbles, 48 in total. the number of blue marbles is 9 more than 2 times the number of red marbles. how many blue marbles are there?

There are 35 blue marbles

Step-by-step explanation:

b = blue marbles

r = red marbles

r+b = 48

b = 2r+9

Substitute b =2r+9 into the first equation

r + (2r+9) = 48

Combine like terms

3r +9 = 48

Subtract 9 from each side

3r+9-9 = 48-9

3r = 39

Divide each side by 3

3r/3 = 39/3

r = 13

There are 13 red marbles

We need to find the blue marbles

b =2r+9

b = 2(13) +9

   = 26+9

   = 35

There are 35 blue marbles