Suppose, 2/3 of 2/3 of a certain quantity of barley is taken, 100 units of barley are added and the original quantity recovered. find the quantity of barley? This is a real question from the Babylonian, posited 4 millenia ago...

1 Answer
Sep 12, 2016

x=180x=180

Explanation:

Let the quantity of barley be xx. As 2/323 of 2/323 of this is taken and 100100 units added to it, it is equivalent to

2/3xx2/3xx x+10023×23×x+100

It is mentioned that this is equal to the original quantity, hence

2/3xx2/3xx x+100=x23×23×x+100=x or

4/9x+100=x49x+100=x or

4/9x-4/9x+100=x-4/9x49x49x+100=x49x or

cancel(4/9x)-cancel(4/9x)+100=x-4/9x=9/9x-4/9x=(9-4)/9x=5/9x or

5/9x=100 or

9/5xx5/9x=9/5xx100 or

cancel9/cancel5xxcancel5/cancel9x=9/5xx100=9/cancel5xx20cancel(100)=180 i.e.

x=180