54. When two quantities are related in such a manner that, if one increases, the other also increases, then they always vary directly. 54. When two quantities are related in such a manner that if one increases the other also increases then they always vary directly. August 5, 2021 Category: Chapter 13 - Direct and Inverse Proportions , Maths , NCERT Class 8 , Facebook Messenger WhatsApp Share this:TwitterFacebook Related