From Dan's ranch one road is built to get to Andy's house and two roads are built to get to Willie's house (see previous problem). How many way are there now to get from Andy's house to Willie's house?

There are ways now to get from Andy's house to Willie's house.

Step-by-step explanation:

Given, from Dan's ranch one road is built to get to Andy's house and two roads are built to get to Willie's house.

Then, the number of ways to get from Andy's house to Willie's house =

(Number of ways to Andy's house) x (Number of ways to get Willie's house)   [Using fundamental counting principle]

= 1 x 2 = 2

Hence, there are ways now to get from Andy's house to Willie's house.

the mistake in the pattern is that :

b. the decimal point was moved one too many place values each time

the correct pattern could be made by :

b. moving the decimal point to the right the same numbers of place values as the exponents