+0  
 
0
48
5
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IF A+B=15,

B+C=20,

C+A=25

THEN

A+B+C ?

 Feb 8, 2020
 #1
avatar+11277 
+2

IF A+B=15,

B+C=20,

C+A=25

THEN

A+B+C ?

 

laugh

 
 Feb 8, 2020
 #2
avatar
+1

Hello,

\(A+B+0C=15\)

\(0A+B+C=20\)

\(A+0B+C=25\)

Add all three

\(2A+2B+2C=60\)

Factor 2

\(2(A+B+C)=60\)

Divide by 2

\(A+B+C=30\)

.
 
 Feb 8, 2020
 #3
avatar+319 
+1

A+B=15      10+5=15

B+C=20       5+15=20

C+A=25      15+10=25

 

A+B+C = 30  indecision

 
 Feb 8, 2020
edited by Guest  Feb 8, 2020
edited by Guest  Feb 8, 2020
 #4
avatar
+1

a+b=15

b+c=20

c+a=25

then add,

a+c=25

b+c=20

a+b=15

2a+2b+2c=60

divide by 2 on both sides and you get

a+b+c=30

 
 Feb 8, 2020
 #5
avatar+26 
0

just add all equations. You will get 2A+2B+2C=60

so A+B+C=60/2 = 30

 

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