Question

3 pumps working in 8 hours a day,can empty the tank in 2days.How many hours a day must 4 pumps would empty the tank in one day? 

Answer 1

[tex]8h\ a\ day\to16h\ in\ 2days\\\\ \begin{array}{ccc}3pumps&-&16h\\\\4pumps&-&xh\end{array}\\\\ This\ is\ the\ inverse\ proportionality\ (the\ product\ is\ a\ constant):\\\\4x=3\times16\\\\4x=48\ \ \ \ |divide\ both\ sides\ by\ 4\\\\x=12\ (h)\\\\Answer:Number\ of\ hours\ taken\ to\ empty\ the\ tank\\by\ 4\ pumps\ equal\ 12.[/tex]