The number of roses was 15 greater than twice the number of prunes. if the roses and prunes totaled 255, how many roses were there?

X=number of roses
y=number of prunes
we can suggest this system of equations:
x+y=255
x=2y+15

We can solve this system of equation by substitution method.
x=2y+15

(2y+15)+y=255
3y=240
y=240/3
y=80

x=2y+15
x=2(80)+15
x=160+15
x=175

there was 175 roses and 80 prunes.