CBSE Class 4 Mathematics Chapter 12: How Heavy How Light - NCERT Solutions

Part 1: Finding the total weight loaded on the cart.

To find the total weight, we add the weights of all the items listed:

• Weight of a water tank = $50\; \backslash text\{\; kg\}$
• Weight of 1 sack of wheat = $100\; \backslash text\{\; kg\}$
• Weight of 1 table = $10\; \backslash text\{\; kg\}$
• Weight of an Amirah = $70\; \backslash text\{\; kg\}$
• Weight of 1 chair = $5\; \backslash text\{\; kg\}$
• Weight of 1 mattress = $20\; \backslash text\{\; kg\}$
• Weight of 1 sack of rice = $35\; \backslash text\{\; kg\}$
• Weight of a bamboo ladder = $10\; \backslash text\{\; kg\}$
• Weight of pots and pans = $10\; \backslash text\{\; kg\}$

Total weight = 50 + 100 + 10 + 70 + 5 + 20 + 35 + 10 + 10 \text{ kg}

Total weight = 310 \text{ kg}

Note: The source document seems to have calculated weights for multiple items (e.g., 5 sacks of wheat, 3 tables, 4 chairs, 2 mattresses, 3 sacks of rice) which were not explicitly stated in the question's table. For this solution, we will use the weights as listed directly in the table for each item type, assuming only one of each item was loaded unless specified otherwise.

Let's re-calculate based on the assumption that the source's detailed calculation implies multiple items were loaded, even if not explicitly stated in the initial table for each item.

Weight of 1 water tank = 50 \text{ kg}

Weight of 1 sack of wheat = 100 \text{ kg}

Weight of 1 table = 10 \text{ kg}

Weight of an Amirah = 70 \text{ kg}

Weight of 1 chair = 5 \text{ kg}

Weight of 1 mattress = 20 \text{ kg}

Weight of 1 sack of rice = 35 \text{ kg}

Weight of 1 bamboo ladder = 10 \text{ kg}

Weight of pots and pans = 10 \text{ kg}

Total weight = 50 + 100 + 10 + 70 + 5 + 20 + 35 + 10 + 10 = 310 \text{ kg}

However, if we follow the calculation provided in the source document which implies multiple items were loaded:

Weight of 1 water tank = 50 \text{ kg}Weight of 1 sack of wheat = 100 \text{ kg}

Weight of 1 table = 10 \text{ kg}

Weight of an Amirah = 70 \text{ kg}

Weight of 1 chair = 5 \text{ kg}

Weight of 1 mattress = 20 \text{ kg}

Weight of 1 sack of rice = 35 \text{ kg}

Weight of 1 bamboo ladder = 10 \text{ kg}

Weight of pots and pans = 10 \text{ kg}

The source calculation implies:

• Weight of 1 water tank = $50\; \backslash text\{\; kg\}$
• Weight of 5 sacks of wheat = $5\; \backslash times\; 100\; \backslash text\{\; kg\}\; =\; 500\; \backslash text\{\; kg\}$
• Weight of 1 table = $10\; \backslash text\{\; kg\}$
• Weight of 3 tables = $3\; \backslash times\; 10\; \backslash text\{\; kg\}\; =\; 30\; \backslash text\{\; kg\}$
• Weight of an Amirah = $70\; \backslash text\{\; kg\}$
• Weight of 1 chair = $5\; \backslash text\{\; kg\}$
• Weight of 4 chairs = $4\; \backslash times\; 5\; \backslash text\{\; kg\}\; =\; 20\; \backslash text\{\; kg\}$
• Weight of 1 mattress = $20\; \backslash text\{\; kg\}$
• Weight of 2 mattresses = $2\; \backslash times\; 20\; \backslash text\{\; kg\}\; =\; 40\; \backslash text\{\; kg\}$
• Weight of 3 sacks of rice = $3\; \backslash times\; 35\; \backslash text\{\; kg\}\; =\; 105\; \backslash text\{\; kg\}$
• Weight of 1 bamboo ladder = $10\; \backslash text\{\; kg\}$
• Weight of pots and pans = $10\; \backslash text\{\; kg\}$

Total weight loaded on the cart = $50\; +\; 500\; +\; 30\; +\; 70\; +\; 20\; +\; 40\; +\; 105\; +\; 10\; +\; 10\; \backslash text\{\; kg\}$

Total weight = $835\; \backslash text\{\; kg\}$

Note: There is a discrepancy in the source's total calculation ($845\; \backslash text\{\; kg\}$). Let's re-sum: $50\; +\; 500\; +\; 30\; +\; 70\; +\; 20\; +\; 40\; +\; 105\; +\; 10\; +\; 10\; =\; 835\; \backslash text\{\; kg\}$. We will proceed with $835\; \backslash text\{\; kg\}$ as the correct total weight based on the items listed in the source's calculation.

Part 2: Determining which things to remove to keep the load under 700 kgs.

The current total weight is $835\; \backslash text\{\; kg\}$. We need to remove items so the weight is not more than $700\; \backslash text\{\; kg\}$. This means we need to remove at least $835\; -\; 700\; =\; 135\; \backslash text\{\; kg\}$.

Let's look at the weights of the items that were multiplied:

• 3 sacks of rice: $105\; \backslash text\{\; kg\}$
• 2 mattresses: $40\; \backslash text\{\; kg\}$
• 4 chairs: $20\; \backslash text\{\; kg\}$
• 3 tables: $30\; \backslash text\{\; kg\}$
• 5 sacks of wheat: $500\; \backslash text\{\; kg\}$
• 1 water tank: $50\; \backslash text\{\; kg\}$
• 1 Amirah: $70\; \backslash text\{\; kg\}$
• 1 bamboo ladder: $10\; \backslash text\{\; kg\}$
• Pots and pans: $10\; \backslash text\{\; kg\}$

To reach a removal weight of at least $135\; \backslash text\{\; kg\}$, we can remove the following:

• Remove 3 sacks of rice ($105\; \backslash text\{\; kg\}$) and 1 bamboo ladder ($10\; \backslash text\{\; kg\}$) and pots and pans ($10\; \backslash text\{\; kg\}$). Total removed = $105\; +\; 10\; +\; 10\; =\; 125\; \backslash text\{\; kg\}$. This is not enough.
• Remove 3 sacks of rice ($105\; \backslash text\{\; kg\}$) and 3 tables ($30\; \backslash text\{\; kg\}$). Total removed = $105\; +\; 30\; =\; 135\; \backslash text\{\; kg\}$.

If we remove the 3 sacks of rice and the 3 tables:

New total weight = $835\; \backslash text\{\; kg\}\; -\; 135\; \backslash text\{\; kg\}\; =\; 700\; \backslash text\{\; kg\}$.

This meets the condition of not being more than 700 kgs.

Answer: The 3 sacks of rice and the 3 tables should be removed so that the weight of the load is not more than 700 kgs.