This chapter uses the context of a dairy farm to practise reading data, working with large numbers, understanding simple averages, and solving word problems involving multiplication, division, and money.
Key Concepts
Large Numbers: We work with numbers in thousands and lakhs when dealing with farm production and income.
Average (Mean): The average is found by adding all values and dividing by the number of values.
Average = Sum of values / Number of values
- Profit and Loss:
- Profit = Selling Price - Cost Price (when SP > CP)
- Loss = Cost Price - Selling Price (when CP > SP)
Reading Data from Tables: Identify the right row and column, then use the values for calculations.
Word Problems: Read carefully to decide which operation (+, -, x, /) to use.
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A farm produces 250 litres of milk on Monday, 310 litres on Tuesday, and 270 litres on Wednesday. Find the average daily production.
Key formulas
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Milk is sold at Rs 40 per litre. A farm sells 500 litres. What is the income?
- Income = 500 x 40 = Rs 20,000
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The cost of feeding the herd for a week is Rs 14,000. The milk income is Rs 17,500. Find the profit.
- Profit = 17,500 - 14,000 = Rs 3,500
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6 cows produce a total of 120 litres of milk per day. What is the average milk per cow?
- Average = 120 / 6 = 20 litres per cow
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A farmer buys 5 calves at Rs 8,500 each. What is the total cost?
- Total = 5 x 8,500 = Rs 42,500
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Key Formulas
Key formulas
Common mistakes
- Forgetting to divide by the correct number of values when finding average.
- Subtracting in the wrong order for profit/loss (always SP - CP for profit).
Summary
Use averages to understand typical values. Total income = Quantity x Rate. Profit = SP - CP; Loss = CP - SP.