Question: How Much Does Each One Weigh?
mashupmath
27.5 LBS
37.5 LBS
Hard Math Problems for 6th Graders: The Pumpkin and Watermelon Problem
Graph/shape description: top-left shows a scale with 3 pumpkins and 2 watermelons weighing 27.5 LBS; top-right shows a scale with 4 pumpkins and 3 watermelons weighing 37.5 LBS.
1. **State the problem:** We have two scales with pumpkins and watermelons. The first scale shows 3 pumpkins and 2 watermelons weighing 27.5 pounds. The second scale shows 4 pumpkins and 3 watermelons weighing 37.5 pounds. We want to find the weight of one pumpkin and one watermelon.
2. **Define variables:** Let $p$ be the weight of one pumpkin and $w$ be the weight of one watermelon.
3. **Write the system of equations:**
$$3p + 2w = 27.5$$
$$4p + 3w = 37.5$$
4. **Solve the system using elimination:**
Multiply the first equation by 3 and the second by 2 to align the coefficients of $w$:
$$3(3p + 2w) = 3(27.5) \Rightarrow 9p + 6w = 82.5$$
$$2(4p + 3w) = 2(37.5) \Rightarrow 8p + 6w = 75$$
5. **Subtract the second equation from the first:**
$$ (9p + 6w) - (8p + 6w) = 82.5 - 75$$
$$ 9p - 8p + \cancel{6w} - \cancel{6w} = 7.5$$
$$ p = 7.5$$
6. **Substitute $p = 7.5$ into the first original equation:**
$$3(7.5) + 2w = 27.5$$
$$22.5 + 2w = 27.5$$
7. **Isolate $w$:**
$$2w = 27.5 - 22.5$$
$$2w = 5$$
$$w = \frac{5}{2} = 2.5$$
8. **Final answer:**
- One pumpkin weighs $7.5$ pounds.
- One watermelon weighs $2.5$ pounds.