+0  
 
0
102
1
avatar

When a certain tree was first planted, it was 4 feet tall, and the heigth of the tree increased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increased each year?

 Dec 16, 2019
 #1
avatar+109748 
+1

Let m  be the constant amount  (in feet) that it grows every year....so.....at the end of 4 years, the height is

[4  + 4m]

 

And  at the end of the  6th year the height  is  4 + 6m

 

And we know that

 

(1 + 1/5)  [ 4 + 4m ] =  4 + 6m

 

(1.2) [ 4 + 4m ]  = 4 + 6m

 

4.8 + 4.8m = 4 + 6m

 

4.8 - 4   = 6m - 4.8m

 

.8 = 1.2m        divide both sides by  1.2

 

.8 / 1.2  =  m  = 8/12  = 2/3 ft  =  8 inches  per year

 

 

 

cool cool cool

 Dec 16, 2019

21 Online Users

avatar
avatar