43. Two quantities x and y are said to vary directly with each other if for some rational number k, xy = k. 43. Two quantities x and y are said to vary directly with each other if for some rational number k xy = k. August 5, 2021 Category: Chapter 13 - Direct and Inverse Proportions , Maths , NCERT Class 8 , Facebook Messenger WhatsApp Share this:TwitterFacebook Related