Step-by-step explanation:
We have got the lines :

Both lines intercept the x-axis in the point :

In all point from x-axis the y-component is equal to 0.

We replace the I point in the lines equations:

From the first equation :

From the second equation :

Then 
Finally :

y = ax + b and y = cx + d have the same x-intercept ⇔ad=bc
(8/9) / 6 =
8/9 * 1/6 =
8/54 which reduces to 4/27 of the book each day <===
The multiplier to get from 6 * ... to 15 is 15/6.
If 6 * 15/6 = 15, then 20 * 15/6 = 50, answer B.
34 just look at your number and you get it