Question

Which of the following proportions is false

12/15 = 20/25
25/45 = 50/90
20/50 = 40/100
18/48 = 30/50

Answer 1

The proportion that is false is 18/48 = 30/50.

Explanation:

To determine which of the given proportions is false, rewrite the fractions on both sides each equation so that the denominators are the same.

`(12)/(15)=(20)/(25) \implies (12 / 3)/(15 / 3)=(20 / 5)/(25 / 5)\implies (4)/(5)=(4)/(5)\qquad \boxed{\sf True}`

`(25)/(45)=(50)/(90) \implies (25 / 5)/(45/ 5)=(50/ 10)/(90/ 10)\implies (5)/(9)=(5)/(9)\qquad \boxed{\sf True}`

`(20)/(50)=(40)/(100) \implies (20/ 10)/(50/ 10)=(40/20)/(100/ 20)\implies (2)/(5)=(2)/(5)\qquad \boxed{\sf True}`

`(18)/(48)=(30)/(50) \implies (18* 25)/(48* 25)=(30* 24)/(50 *24)\implies (450)/(1200)= (720)/(1200)\qquad \boxed{\sf False}`

Therefore, the proportion that is false is 18/48 = 30/50.