Answer :
Let's go through each scenario one by one:
Books in the Bookstore:
- The bookstore has 5 different types of books, each with 12 copies. This means the total number of books is [tex]5 \times 12 = 60[/tex] copies.
- They sell 30 copies in total, so the number of copies left is [tex]60 - 30 = 30[/tex] copies.
- Since the copies are evenly divided after sales, each type has approximately [tex]\frac{30}{5} = 6[/tex] copies left.
- Option C: 6
Flowers in the Garden:
- There are 8 rows with 15 flowers in each, so the total number of flowers is [tex]8 \times 15 = 120[/tex] flowers.
- After 20 flowers die, the number of flowers left is [tex]120 - 20 = 100[/tex] flowers.
- Option A: 100
Toys Produced by the Factory:
- The factory produces 250 toys per hour and operates for 8 hours, making [tex]250 \times 8 = 2000[/tex] toys.
- With 300 defective toys, the number of good toys is [tex]2000 - 300 = 1700[/tex], but since this isn't an option, we must have an error in reading; therefore, from given, the closest would need review based on additional options.
- With re-check: None of provided options match considering context.
Car Distance Travelled:
- The car can travel 30 miles per gallon. With 10 gallons, it can go [tex]10 \times 30 = 300[/tex] miles.
- After using 4 gallons, the driver has 6 gallons left. The distance the car can travel now is [tex]6 \times 30 = 180[/tex] miles.
- Option A: 180
Cookies Baked by the Chef:
- The chef makes 4 batches, each with 24 cookies, for a total of [tex]4 \times 24 = 96[/tex] cookies.
- After giving away 36 cookies, [tex]96 - 36 = 60[/tex] cookies are left.
- Option A: 60
Students in the School:
- There are 12 classes with 25 students each, totaling [tex]12 \times 25 = 300[/tex] students.
- After 15 students transfer, [tex]300 - 15 = 285[/tex] students remain.
- Option A: 285
Gadgets in the Factory:
- Production is 150 gadgets per day, and for 5 days, it's [tex]150 \times 5 = 750[/tex] gadgets.
- With 600 gadgets sold, [tex]750 - 600 = 150[/tex] gadgets are left.
- Re-evaluation needed: Initial set prevents alignment.
Runner's Marathon Training:
- For 6 days she runs 10 miles each, totaling [tex]6 \times 10 = 60[/tex] miles.
- With an extra 5 miles on the last day, she runs [tex]60 + 5 = 65[/tex] miles in total.
- Option A: 65
Each solution process involves simple multiplication and subtraction, which is suitable for middle school students learning basic arithmetic operations.