+0  
 
0
42
1
avatar

David's savings was 75% as much as Alan. After Alan saved another $40 and David saved another $20, David's savings became 5/8 as much as Alan. Find David's savings at first.

 Sep 6, 2023
 #1
avatar+129185 
+1

D =  .75A     →   D / .75 =  A  →  D / (3/4)  = A  →  (4/3) D  = A       (1)

 

(D + 20)  = (5/8) ( A + 40)          (2)

 

Sub ( 1)  into (2)

 

D + 20 =  (5/8) [ (4/3)D  + 40]

 

D + 20 =  (20/24)D + (5/8) (40)

 

D + 20  = (5/6)D + 25

 

D - (5/6)D =  25  -20

 

(1/6)D =  5

 

D = 5 ( 6/1)  =  30

 

David had $30 at first

 

cool cool cool

 Sep 6, 2023

4 Online Users

avatar
avatar