Answer:
2.4 years
Step-by-step explanation:
you have to first convert the trees' heights into inches. three feet is equivalent to 36 inches and four feet is equivalent to 48 inches. Since three A grows at 15 inches a year it'll become a the expression 15x+36 and the expression for tree B will be 10x+48. You set them up to each other and simplify it.
15x+36=10x+48
 -10x     -10x
5x+36=48
  -36     -36
5x=12
/5 Â Â /5
x=2.4
So it'll be 2.4 years