If she weeded 40% of her garden in 8 minutes, we can add another 40% weeded if we add 8 more minutes -
40% + 40% = 80%
8 + 8 = 16 minutes
We need 20% more to reach 100% of her garden. Since 20% is ½ of 40%, we just divide the rate in half -
40%(÷2) in 8(÷2) minutes = 20% in 4 minutes
80% + 20% = 100%
16 + 4 = 20 minutes
Therefore, it takes Paula 20 minutes to weed her entire garden.