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Abby, Bart, Cindy and Damon weigh themselves in pairs. Together Abby and Bart weigh 260 pounds, Bart and Cindy weigh 245 pounds, and Cindy and Damon weigh 270 pounds. How many pounds do Abby and Damon weigh together?

 

Thank you

 Sep 14, 2019

Best Answer 

 #1
avatar+6192 
+1

\(a + b = 260\\ b+c = 245 \\ c+d = 270\\~\\ a+d = (a+b) +(c+d) - (b+c) = \\ 260+270-245 = 285\)

.
 Sep 14, 2019
 #1
avatar+6192 
+1
Best Answer

\(a + b = 260\\ b+c = 245 \\ c+d = 270\\~\\ a+d = (a+b) +(c+d) - (b+c) = \\ 260+270-245 = 285\)

Rom Sep 14, 2019
 #2
avatar
+1

A+B=260   (1)

B+C=245  (2)

C+D=270  (3)

 

 

It's system of equations

 

(2) multiply by -1

we get:

-B-C=-245

Add (2) to (1)

A+B=260

+

-B-C= -245 

=

A-C=15

 

Now let's add (3) to A-C=15

C+D=270

+

A-C=15

A+D=285 Solved 

 Sep 14, 2019

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