The third dart earned Don 50 / 2 = 25 points. Thus, his total score is 50 + 0 + 25 = 75 points.
The answer: 75
Reverse engineering the question: Don throws 3 darts. One is a bullseye worth 50 points. One completely missed the target, so received no points. The third was worth half the points of the bullseye. What is the final score from these 3 throws?

Multiply the number of shells collected each day by 6, to get the total number of seashells Evie has collected: 10 x 6 = 60 seashells. Subtract the 2 shells she gave her brother, to get the number of shells she has left: 60 - 2 = 58 seashells.
The answer: 58
Reverse engineering the question: Evie is collecting seashells while at the beach. Each day she collects her favorite 10 shells. At the end of 6 days, she gives 2 shells to her brother. How many shells does she have left?

In the first part of her trip, Diana will cover 2 hours * 3 mph = 6 miles. In the second part of her trip, Diana will need to cover an additional 10 miles - 6 miles = 4 miles. To cover 4 miles * 1 mph = will take Diana 4 hours. Total biking time to get home for Diana will be 2 hours + 4 hours = 6 hours.
The answer: 6
Reverse engineering the question: Diana needs to bike 10 miles to get home. She can bike 3 mph for two hours before she gets tired, and she can bike 1 mph until she gets home. How long will it take Diana to get home?

60% of female alligators are adults because 100 - 40 = 60. There are 25 female alligators because 15 / .6 = 25. There are 50 alligators in total because 25 / .5 = 50. There are 25 male alligators because 50 / 2 = 25.
The answer: 25
Reverse engineering the question:
Lagoon island is populated by alligators. Half the alligators are male. The rest are female. Among the females, 40% are juveniles. There are 15 adult females. How many male alligators are there?