The teacher divided the students into four groups. One group had 5 students, another 8 students, and the third 7 students. If there were 24 total students, how many students were in the fourth group?
Let's think: There are 5 + 8 + 7 = 20 students in the first three groups. There are 24 - 20 = 4 students in the fourth group.. The answer is: 4.

Brooke is milking cows and then selling the milk at the market for $3 a gallon. Whatever milk doesn't sell, she turns into butter. One gallon of milk equals 2 sticks of butter. She then sells the butter for $1.5 a stick. She has 12 cows. Each cow produces 4 gallons of milk. She has 6 customers, each of whom wants 6 gallons of milk. How much money does she earn if she sells all her milk and butter?
Let's think: A gallon of milk makes $3 worth of butter because 2 x 1.5 = 3. A gallon of milk sells for the same amount as milk or butter because 3 = 3. She gets 48 gallons of milk because 4 x 12 = 48. She earns $144 selling the milk because 48 x $3 = 144.. The answer is: 144.

Maggie went to Lou's aquarium and saw 100 goldfish in the aquarium. She asked if she could take some home to care for, and she was allowed to catch half of them. While using a catching net, she caught 3/5 of the total number of goldfish she was allowed to take home. How many goldfish does Maggie remain with to catch to get the total number she was allowed to take home?
Let's think: Maggie was allowed to take half of the goldfish in the aquarium, a total of 1 / 2 * 100 = 50 goldfish. On her first catch, Maggie got 3 / 5 * 50 = 30 goldfish. To reach the number of goldfish she was allowed to take home, Maggie has to catch 50 - 30 = 20 more goldfish.. The answer is: 20.

Andy harvests all the tomatoes from 18 plants that have 7 tomatoes each. If he dries half the tomatoes and turns a third of the remainder into marinara sauce, how many tomatoes are left?
Let's think:
First find the total number of tomatoes harvested: 18 plants * 7 tomatoes / plant = 126 tomatoes. Then divide that number by 2 to find how many tomatoes are left undried: 126 tomatoes / 2 = 63 tomatoes. Then divide that number by 3 to find how many tomatoes are turned into sauce: 63 tomatoes / 3 = 21 tomatoes. Then subtract that number from the number of undried tomatoes to find the remaining number of tomatoes: 63 tomatoes - 21 tomatoes = 42 tomatoes.. The answer is: 42.