Question

To make lemonade, 2 cups of lemon juice are mixed with 7 cups of water.Describe and correct the error in proportion used to find the number of cups of lemonade juice, j , to mix with 28 cups of water. 2/7 = 28/j

Answer 1

x/9 = 8/36 
x = 9 * 8/36 [multiplying each side by 9] 
x = 2 
 
x/90 = 4.4/12 
x = 90 * 4.4/12 [multiplying each side by 90] 
x = 33 

Both proportions should be expressed as lemon juice to water, or water to lemon juice. Either way would give a correct answer: 
2/7 = j/28 [lemon juice to water] 
8 = j [multiplying each side by 28] 

7/2 = 28/j [water to lemon juice] 
7j = 56 [multiplying each side by 2j] 
j = 8 [dividing each side by 7] 


The length proportion is 24 in to 32 ft. 
The actual house is 24 ft tall. 
Let x represent the doll house height, in inches. Then 
x/24 = 24/32 
x = 24 * 24/32 = 18 inches