Printable primary math worksheet for math grades 1 to 6 based on ... - Free Printable

Let's solve each problem step by step:

---

Problem 1:

I can read 120 words per 12 minutes. How many hours will it take me to read a book with 6,000 words?

#### Solution:
1. Find the reading rate in words per minute:
\[
\text{Words per minute} = \frac{120 \text{ words}}{12 \text{ minutes}} = 10 \text{ words per minute}
\]

2. Calculate the total time needed to read 6,000 words:
\[
\text{Total time (in minutes)} = \frac{6,000 \text{ words}}{10 \text{ words per minute}} = 600 \text{ minutes}
\]

3. Convert minutes to hours:
\[
\text{Total time (in hours)} = \frac{600 \text{ minutes}}{60 \text{ minutes per hour}} = 10 \text{ hours}
\]

Answer:
\[
\boxed{10}
\]

---

Problem 2:

A car’s top speed is 120 miles per hour. How many minutes will it take the car to drive 50 miles at top speed?

#### Solution:
1. Find the time taken to travel 50 miles:
\[
\text{Time (in hours)} = \frac{\text{Distance}}{\text{Speed}} = \frac{50 \text{ miles}}{120 \text{ miles per hour}} = \frac{5}{12} \text{ hours}
\]

2. Convert hours to minutes:
\[
\text{Time (in minutes)} = \frac{5}{12} \times 60 = 25 \text{ minutes}
\]

Answer:
\[
\boxed{25}
\]

---

Problem 3:

A car factory can produce 3 cars per 2 minutes. If the factory opens for production at 8:30 am and closes at 5:30 pm, how many cars can the factory produce in a day?

#### Solution:
1. Calculate the total production time in minutes:
- The factory operates from 8:30 am to 5:30 pm.
- Total time = \(5:30 \text{ pm} - 8:30 \text{ am} = 9 \text{ hours}\).
- Convert hours to minutes:
\[
9 \text{ hours} \times 60 \text{ minutes per hour} = 540 \text{ minutes}
\]

2. Find the production rate in cars per minute:
\[
\text{Cars per minute} = \frac{3 \text{ cars}}{2 \text{ minutes}} = 1.5 \text{ cars per minute}
\]

3. Calculate the total number of cars produced in 540 minutes:
\[
\text{Total cars} = 1.5 \text{ cars per minute} \times 540 \text{ minutes} = 810 \text{ cars}
\]

Answer:
\[
\boxed{810}
\]

---

Problem 4:

A bakery store can bake 12 breads per hour. How many minutes does it take the bakery to bake 3 breads?

#### Solution:
1. Find the baking rate in breads per minute:
\[
\text{Breads per minute} = \frac{12 \text{ breads}}{60 \text{ minutes}} = 0.2 \text{ breads per minute}
\]

2. Calculate the time needed to bake 3 breads:
\[
\text{Time (in minutes)} = \frac{3 \text{ breads}}{0.2 \text{ breads per minute}} = 15 \text{ minutes}
\]

Answer:
\[
\boxed{15}
\]

---

Problem 5:

In the supermarket, the price of 4 kilograms of sugar is $3. What is the price of 120 kilograms of sugar?

#### Solution:
1. Find the price per kilogram of sugar:
\[
\text{Price per kilogram} = \frac{\$3}{4 \text{ kilograms}} = \$0.75 \text{ per kilogram}
\]

2. Calculate the price of 120 kilograms:
\[
\text{Total price} = 120 \text{ kilograms} \times \$0.75 \text{ per kilogram} = \$90
\]

Answer:
\[
\boxed{90}
\]

---

Problem 6:

I can walk 20 kilometers in 5 hours. If I walk at this speed, how long will it take me to walk 200 meters?

#### Solution:
1. Find the walking speed in kilometers per hour:
\[
\text{Speed} = \frac{20 \text{ kilometers}}{5 \text{ hours}} = 4 \text{ kilometers per hour}
\]

2. Convert 200 meters to kilometers:
\[
200 \text{ meters} = \frac{200}{1000} \text{ kilometers} = 0.2 \text{ kilometers}
\]

3. Calculate the time needed to walk 0.2 kilometers:
\[
\text{Time (in hours)} = \frac{\text{Distance}}{\text{Speed}} = \frac{0.2 \text{ kilometers}}{4 \text{ kilometers per hour}} = 0.05 \text{ hours}
\]

4. Convert hours to minutes:
\[
\text{Time (in minutes)} = 0.05 \text{ hours} \times 60 \text{ minutes per hour} = 3 \text{ minutes}
\]

Answer:
\[
\boxed{3}
\]

---

Final Answers:

1. \(\boxed{10}\)
2. \(\boxed{25}\)
3. \(\boxed{810}\)
4. \(\boxed{15}\)
5. \(\boxed{90}\)
6. \(\boxed{3}\)