Math Problem Statement

I can walk 5 1/8 km in an hour. What distance will I cover in 3 1/8 hours? The cost of one chocolate bar is Rs 9 2/7. What is the cost of 9 such chocolate bars? One kg of apples costs Rs 68 1/3. What is the cost of 2 1/4 kg of apples? One litre of petrol costs Rs 76 8/9. What is the cost of 33 litres of petrol? A bag contains 52 4/5 kg of sugar. How much sugar do 8 such bags contain?

Solution

The image you shared contains word problems related to multiplication of fractions. Let's solve each exercise one by one.

Exercise 4.4

1. I can walk 5185 \frac{1}{8} km in an hour. What distance will I cover in 3183 \frac{1}{8} hours?

  • Convert the mixed fractions into improper fractions: 518=418,318=2585 \frac{1}{8} = \frac{41}{8}, \quad 3 \frac{1}{8} = \frac{25}{8}
  • Multiply the two fractions: Distance=418×258=41×258×8=102564=16164 km\text{Distance} = \frac{41}{8} \times \frac{25}{8} = \frac{41 \times 25}{8 \times 8} = \frac{1025}{64} = 16 \frac{1}{64} \text{ km}

2. The cost of one chocolate bar is Rs 9279 \frac{2}{7}. What is the cost of 9 such chocolate bars?

  • Convert the mixed fraction into an improper fraction: 927=6579 \frac{2}{7} = \frac{65}{7}
  • Multiply the cost by 9: Cost of 9 bars=9×657=5857=8347 Rs\text{Cost of 9 bars} = 9 \times \frac{65}{7} = \frac{585}{7} = 83 \frac{4}{7} \text{ Rs}

3. One kg of apples costs Rs 681368 \frac{1}{3}. What is the cost of 2142 \frac{1}{4} kg of apples?

  • Convert the mixed fractions into improper fractions: 6813=2053,214=9468 \frac{1}{3} = \frac{205}{3}, \quad 2 \frac{1}{4} = \frac{9}{4}
  • Multiply the two fractions: Cost=2053×94=205×912=184512=153912=15334 Rs\text{Cost} = \frac{205}{3} \times \frac{9}{4} = \frac{205 \times 9}{12} = \frac{1845}{12} = 153 \frac{9}{12} = 153 \frac{3}{4} \text{ Rs}

4. One litre of petrol costs Rs 768976 \frac{8}{9}. What is the cost of 33 litres of petrol?

  • Convert the mixed fraction into an improper fraction: 7689=692976 \frac{8}{9} = \frac{692}{9}
  • Multiply by 33: Cost of petrol=33×6929=228369=253739=253713 Rs\text{Cost of petrol} = 33 \times \frac{692}{9} = \frac{22836}{9} = 2537 \frac{3}{9} = 2537 \frac{1}{3} \text{ Rs}

5. A bag contains 524552 \frac{4}{5} kg of sugar. How much sugar do 8 such bags contain?

  • Convert the mixed fraction into an improper fraction: 5245=264552 \frac{4}{5} = \frac{264}{5}
  • Multiply by 8: Sugar in 8 bags=8×2645=21125=42225 kg\text{Sugar in 8 bags} = 8 \times \frac{264}{5} = \frac{2112}{5} = 422 \frac{2}{5} \text{ kg}

Would you like more details or further clarification on any of these steps?

Here are 5 related questions to further your understanding:

  1. How can you simplify the multiplication of improper fractions?
  2. What is the method to convert mixed fractions into improper fractions?
  3. How would you solve if the fractions involved had larger numerators or denominators?
  4. What is the practical use of multiplication of fractions in real-life scenarios like shopping?
  5. How can you estimate answers quickly before multiplying fractions?

Tip: Always convert mixed fractions to improper fractions first when performing operations like multiplication or division.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Multiplication of Fractions
Conversion of Mixed Fractions to Improper Fractions

Formulas

Convert mixed fraction to improper fraction: a b/c = (a * c + b) / c
Multiplication of fractions: (a/b) * (c/d) = (a * c) / (b * d)

Theorems

-

Suitable Grade Level

Grade 5-7