Alyssa's lemonade recipe calls for 9 lemons for every 2.5 gallons
of water. Brian's recipe calls for 12 lemons for every 4 gallons of
water. Whose lemonade will require more water if they each use
36 lemons?

Brian's recipe of lemonade requires more water than Alyssa's lemonade recipe.

Step-by-step explanation:

For Alyssa's recipe,

2.5 gallons of water needed for 9 lemons.

So for 36 lemons,   = 10 gallons of water needed

For Brian's recipe,

4 gallons of water needed for 12 lemons,

So for 36 lemons,  = 12 gallons of water needed.

So Brian's recipe needs more water when compared to Alyssa's recipe.

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