Mr. Smith is painting the wall but not the door. A gallon of paint will cover 200 square feet. How many gallons of paint will Mr. Smith need to purchase?

0.16 or 16%

step-by-step explanation:

lets take a coin for example.

if you toss it twice, it has a 1/4 chance of landing on heads both times because 1/2 * 1/2 is 1/4.

with the cards, the chance of picking dog is 0.4. having two people pick one is like picking a card twice in a row. so 0.4 * 0.4 is 0.16, or 16%

47 - 90 = 43

43 - 180 = x

x = 137