What were the revenues of each corporation?

Question

the two companies with top revenues in the fortune 500 list for 2012 were Exxon Mobil and Walmart. Their revenues together totaled $919.1 billion. Exxon mobile revenues were $19.3 billion less than those of Walmart. What were the revenues of each corporation?

Answer 1

We'll use E for Exxon Mobil's revenues in billions of dollars and W for Walmart's revenue in billions of dollars.

 

We know that the combined revenues of both Exxon Mobil and Walmart sum to $919.1 billion thus:

E + W = 919.1

We also know that Exxon Mobil's revenues is $19.3 billion less than those of Walmart. Thus:

 

E = W - 19.3

We now have 2 equations and 2 unknowns:

 

E + W = 919.1

& 

E = W - 19.3

You can directly plug in the 2nd equation into the 1st equation to solve for W or Walmart's revenues in billions of dollars. Afterwards, plug the value of W back into the 2nd equation to solve for Exxon Mobil's revenues in billions of dollars.

Hope it goes well.