Alice, Bob, and Charlie are three siblings with ages a, b, and c respectively. Their combine age is 18 years. Charlie is older than Bob. Alice's age is equal to twice the difference between Bob's and Charlie's ages. Bob's age is equal the average of Alice's and Charlie's ages.

Question

(a)Use the information provided to formulate a system of three equations for a, b, and c.

(b)Solve the system using row reduction techniques, or otherwise.

Answer 1

What's the trouble? Just start writing the words as equations. We are told:

a+b+c = 18
a = 2(c-b) (because c > b)
b = (a+c)/2

Now just go through the usual procedures to solve several equations.

Answer 2

i dunno so stop