capacity of 6 pitchers and 12 glasses is 21 liters. The capacity of pitcher is 5 times that of a glass. Find the capacity of each glass. Give answer in liters.

Question

I have no idea how to solve this problem

Answer 1

Let the capacity of a pitcher be p and that of a glass be g

 

p = 5*g

 

6p +12g = 21

 

substituting for a pitcher in the above

 

6(5g) +12g = 21

 

30g + 12g = 21

 

42g = 21, therefore g = 21/42 = 0.5 liters

 

p = 5 * 0.5 = 2.5 liters

 

Check; 6*2.5 + 12*0.5 = 15 + 6 = 21 liters (proven)

Answer 2

Let's assume that capacity of a glass is x (l). Then capacity of a pitcher is 5x. We know that 6 pitchers (6*5x) + capacity of 12 glasses (12x) is 21 l.

Our equation is 6*5x +12x = 21, or 30x +12x = 21, or 42x  = 21, or (42/42)x = 21/42, or x = 1/2 = 0.5 l.