Let z be the number of zoology books and b be the number of botany books. We know that z + b = 80 and b = 4z. Substituting the second equation into the first equation, we get z + 4z = 80. Combining like terms, we get 5z = 80. Dividing both sides by 5, we get z = 16.
The answer: 16
Reverse engineering the question: Milton has some books about zoology and 4 times as many books about botany. If he has 80 books total, how many zoology books does he have?

He needs 10 cans because 80 / 8 = 10. He spends $5 because 10 x .5 = 10.
The answer: 5
Reverse engineering the question: Peter needs 80 ounces of soda for his party. He sees that 8 oz cans cost $.5 each. How much does he spend on soda if he buys the exact number of cans he needs?

Dustin reads 1.25 pages a minute because 75 / 60 = 1.25. Dustin reads 50 pages in 40 minutes because 40 x 1.25 = 50. Sam reads .4 pages a minute because 24 / 60 = .4. Sam reads 16 pages in 40 minutes because 40 x .4 = 16. Dustin reads 34 more pages than Sam because 50 - 16 = 34.
The answer: 34
Reverse engineering the question: Dustin and Sam are both reading. Dustin can read 75 pages in an hour. Sam can read 24 pages in an hour. How many more pages does Dustin read in 40 minutes compared to Sam?

Jackson gets a total of 6x5 = 30 fishes after the competition. Jonah gets 4x5 = 20 fishes after the competition. And George was able to get 8x5 = 40 fishes after the competition. Therefore the total fishes they were able to get for their team is 30 + 20 + 40 = 90.
The answer: 90
Reverse engineering the question:
In a 5-day Fishing competition, Jackson was able to reel a total of 6 fishes per day, Jonah was able to reel 4 fishes per day and George was able to reel 8 fishes per day. How many fishes were they able to catch throughout the competition if they are on the same team?