SOLUTION: The sum of two numbers is 100. If one number is four times the other find the numbers?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: The sum of two numbers is 100. If one number is four times the other find the numbers?      Log On


   

Question 935505: The sum of two numbers is 100. If one number is four times the other find the numbers?
Found 2 solutions by Fombitz, Horlaye:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
A%2BB=100
.
.
A=4B
Substituting,
4B%2BB=100
5B=100
B=20
Then,
A=4%2820%29
A=80

Answer by Horlaye(27) About Me  (Show Source):
You can put this solution on YOUR website!
Let the two numbers be a and b respectively
From the 1st sentence
a+b = 100.......(1)
From the 2nd sentence
a = 4(b)
a = 4b
a-4b = 0...........(2)
Eliminate equation (2) from equation (1)
5b = 100
b = 100/5
b = 20
Substitute b = 20 in equation (2)
a-4b = 0
a-4(20) = 0
a-80 = 0
a = 80
Since a and b represented the two numbers
Therefore the numbers are 80 and 20