Drinks and Burgers Puzzle - Solution

The Puzzle:

Drinks and Burgers
Given that:
1 bottle of drink + 1 bottle of drink + 1 bottle of drink = 30
1 bottle of drink + 1 cheeseburger + 1 cheeseburger = 20
1 cheeseburger + 2 glasses of drink + 2 glasses of drink = 9

Try to find the answer to this:
1 cheeseburger + 1 glass of drink × 1 bottle of drink = ?

Our Solution:

From the 1st: bottle of drink = 10 (10+10+10=30)
From the 2nd: cheeseburger = 5 (10+5+5=20)
From the 3rd: glass of drink = 1 (5+2x1+2x1=9)

So:
1 cheeseburger + 1 glass of drink × 1 bottle of drink
= 5 + 1 × 10
= 5 + 10
= 15
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