Name: sameer

Who is asking: Parent
Level: Elementary

Question:

a+b+c=180
b=a+(120/2-5)
c=b-(130-10)/6
a=?
b=?
c=?



Hi Sameer,

I want to start by simplifying the right side of the second and third exprressions.

 120/2 - 5 = 60 - 5 = 55 thus b = a + 55 Also  (130 - 10)/6 = 120/6 = 20 hence c = b - 20

Now look at the first exprerssion, a + b + c = 180. Since c = b + 20 we can replace c in the first expression by b - 20 to get

a + b + (b - 20) = 180 that is a + 2b - 20 = 180 and hence a + 2b = 200

But the second equation we know now says b = a + 55 and hence

a + 2(a + 55) = 200 thus a + 2a + 110 = 200 or 3a = 90 Hence a = 30.

Now you can use the simplified second equation to find b and then the simplifies third equation to find c. You should then check your answer by substituting the values of a, b and c you found into the original three equations to make sure they are valid.

Penny

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