Robert is serving 16 drinks to his friends. Three times as many friends are drinking lemonade as tea, and 4 are drinking water. How many of each type of drink does Robert serve?

9 lemonade, 3 tea, 4 water

Robert should serve 3 for tea, 9 for lemonade, and 4 for water.

Step-by-step explanation:

Since you don't know how many friends are drinking lemonade or tea, you should give them variables.

x = amount of friends drinking tea

3x = amount of friends drinking lemonade

We already know how many are drinking water, so there's no need for a variable.

Then, make an equation:

x + 3x + 4 = 16

Simplify:

4x + 4 = 16

Isolate the variable by subtracting 4 from both sides:

4x = 12

Isolate the variable by dividing both sides by 4:

x = 3, so 3 friends are drinking tea

3x = 9, so 9 friends are drinking lemonade

Double check the work by replacing the variables with their actual numbers:

3 + 9 + 4 = 16

Simplify:

16 = 16

Therefore, the answer is correct.

step-by-step explanation:

∆abc has the points a(1, 7), b(-2, 2), and c(4, 2) as its vertices. formed with the point d(1, 2) as its third vertex, then ∆abd is triangle.