A rubber tree is 95 inches tall and growing at a rate of 4 inches per year. A cactus is 40 inches tall and growing at arate of 5 inches per year. After how many years will the rubber tree be shorter than the cactus tree

The rubber tree starts off at 95 in and increases 4in per year. We can write this as 95 + 4y (y representing the number of years) the cactus tree starts off at 40 in and increases 5 in per year so we can write is as 40 + 5y. We want to find out y when the cactus is taller so
95+4y < 40+5y And we solve for y
Subtract 40 from both sides
55+4y < 5y
Subtract 4y from both sides
55 < y
Y is any number over 55 but we need the year when the cactus will be taller
So in 56 years the cactus will be taller.