Answer:
11 yellow marbles
Step-by-step explanation:
Let y= yellow marbles
r = red marbles
There are 16 total marbles
y+r = 16
the number of yellow marbles is 1 more than twice the red marbles
y =2r+1
Taking y+r = 16 and solving for r
r = 16-y
Substituting this into the second equation
y = 2(16-y) +1
Distribute
y = 32 -2y +1
Add 2y to each side
y +2y = 32 -2y +2y+1
3y = 33
Divide each side by 3
3y/3 =33/3
y= 11
There are 11 yellow marbles
