some years ago, Marcus planted a 7-foot tree in his front yard. The tree grew 3 feet each year. Now the tree is four times the original height.
How many years ago did Marcus plant the tree?
9 years ago because 7*4=28, and 28/3 is 9.
No, Cece.
4 * 7 = 28
28 - 7 = 21
21/3 = ?
height = 3x + 7 , where x is the number of years
when is 3x+7 = 28 ?
3x = 21
x = 7
It will take 7 years to grow to 28 ft
check:
now -- 7
after 1 year -- 10
2years -- 13
3 years --16
4 years -- 19
5 years -- 22
6 years -- 25
7 years -- 28
To find out how many years ago Marcus planted the tree, we need to work backwards using the given information.
Let's assume that "x" represents the number of years ago that Marcus planted the tree.
Since the tree grew by 3 feet each year, the current height of the tree can be calculated as:
Original height + (3 feet * x)
Current height = 7 feet + (3 feet * x)
According to the problem, the current height of the tree is four times the original height:
4 * original height = current height
Substituting the calculated current height into this equation, we get:
4 * 7 feet = 7 feet + (3 feet * x)
Simplifying this equation, we can write:
28 feet = 7 feet + 3x
Next, let's isolate the variable "x" by moving the constant term 7 feet to the right side of the equation:
28 feet - 7 feet = 3x
21 feet = 3x
Finally, we can solve for "x" by dividing both sides of the equation by 3:
21 feet / 3 = 3x / 3
7 = x
Therefore, Marcus planted the tree 7 years ago.