Let's solve each problem step by step.
---
1. David takes 3 hrs to paint a room. Sara takes 6 hrs to complete the same job. If they work together, how long will they take to complete the task?
Solution:
- David’s rate = $ \frac{1}{3} $ of the room per hour
- Sara’s rate = $ \frac{1}{6} $ of the room per hour
Together, their combined rate:
$$
\frac{1}{3} + \frac{1}{6} = \frac{2}{6} + \frac{1}{6} = \frac{3}{6} = \frac{1}{2}
$$
So together, they paint $ \frac{1}{2} $ of the room per hour.
Time to paint the whole room:
$$
\frac{1}{\frac{1}{2}} = 2 \text{ hours}
$$
✔ Answer: 2 hours
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2. Find three consecutive odd integers such that the sum of twice the first, the second, and three times the third is 152.
Solution:
Let the three consecutive odd integers be:
- First: $ x $
- Second: $ x + 2 $
- Third: $ x + 4 $
According to the problem:
$$
2x + (x + 2) + 3(x + 4) = 152
$$
Simplify:
$$
2x + x + 2 + 3x + 12 = 152 \\
6x + 14 = 152
$$
Subtract 14:
$$
6x = 138
$$
Divide by 6:
$$
x = 23
$$
So the numbers are:
- 23, 25, 27
✔ Answer: 23, 25, 27
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3. Nancy bought a soft drink for $4 and 8 candy bars. She spent a total of $28. How much did each candy bar cost?
Solution:
Let the cost of one candy bar be $ x $.
Total cost:
$$
4 + 8x = 28
$$
Subtract 4:
$$
8x = 24
$$
Divide by 8:
$$
x = 3
$$
✔ Answer: Each candy bar costs $3.
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4. A rectangle is 2 m tall and 4 m wide. If its width is enlarged to 5 m without changing its perimeter, then find the new length of the rectangle?
Solution:
Original dimensions:
- Length = 4 m
- Width = 2 m
Perimeter:
$$
P = 2(l + w) = 2(4 + 2) = 2(6) = 12 \text{ m}
$$
Now, width becomes 5 m, perimeter stays 12 m.
Let new length be $ l $.
$$
2(l + 5) = 12 \\
l + 5 = 6 \\
l = 1
$$
✔ Answer: New length is
1 meter
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5. Mary bought one seedless watermelon for $1. How many seedless watermelons can she buy for $11?
Solution:
Each watermelon costs $1 → So for $11:
$$
\frac{11}{1} = 11
$$
✔ Answer: 11 watermelons
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6. The sum of three consecutive even numbers is 156. What is the smallest number?
Solution:
Let the three consecutive even numbers be:
- $ x $
- $ x + 2 $
- $ x + 4 $
Sum:
$$
x + (x + 2) + (x + 4) = 156 \\
3x + 6 = 156 \\
3x = 150 \\
x = 50
$$
✔ Answer: The smallest number is
50
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✔ Final Answers Summary:
1.
2 hours
2.
23, 25, 27
3.
$3 per candy bar
4.
1 meter
5.
11 watermelons
6.
50
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Parent Tip: Review the logic above to help your child master the concept of equations word problems worksheet.