Maharashtra Board Class 7 Maths Chapter 15 Set 54 Statistics Solutions

Question 1. The daily rainfall for each day of a week in a certain city is given in millimeters. Find the average rainfall during the week. 9, 11, 8, 20, 10, 16, 12
Answer: Solution: Average rainfall during the week \( = \frac{\text{sum of rainfall for each day of the week}}{\text{number of days}} \)
\( = \frac{9+11+8+20+10+16+12}{7} \)
\( = \frac{86}{7} \)
\( = 12.285 \approx 12.29 \)
\( \therefore \) The average rainfall during the week is 12.29 mm.
In simple words: To find the average rainfall, sum up all the daily rainfall values and divide by the number of days (7). The result is approximately 12.29 mm.

🎯 Exam Tip: Always remember to round off to two decimal places when dealing with averages involving decimals, unless specified otherwise, and include the correct units.

Question 2. During the annual function of a school, a Women's Self-help Group had set up a snacks stall. Their sales every hour were worth Rs 960, Rs 830, Rs 945, Rs 800, Rs 847, Rs 970 respectively. What was the average of the hourly sales?
Answer: Solution: Average hourly sales \( = \frac{\text{sum of sales every hour}}{\text{number of hours}} \)
\( = \frac{960+830+945+800+847+970}{6} \)
\( = \frac{5352}{6} \)
\( = \text{Rs } 892 \)
\( \therefore \) The average of the hourly sales was Rs 892.
In simple words: To calculate the average hourly sales, add up all the hourly sales figures and divide by the total number of hours (6). The average sales turn out to be Rs 892.

🎯 Exam Tip: Ensure all values are correctly added before dividing. Pay attention to the units (Rs.) in your final answer.

Question 3. The annual rainfall in Vidarbha in five years is given below. What is the average rainfall for those 5 years? 900 mm, 650 mm, 450 mm, 733 mm, 400 mm.
Answer: Solution: Average rainfall for 5 years \( = \frac{\text{sum of annual rainfall in five years}}{\text{number of years}} \)
\( = \frac{900+650+450+733+400}{5} \)
\( = \frac{3133}{5} \)
\( = 626.6 \)
\( \therefore \) The average rainfall in Vidarbha for 5 years was 626.6 mm.
In simple words: To find the average annual rainfall, sum the rainfall measurements over five years and divide by 5. The average rainfall is 626.6 mm.

🎯 Exam Tip: Calculations should be precise, especially when dealing with multiple numbers. Double-check your addition and division.

Question 4. A farmer bought some sacks of animal feed. The weights of the sacks are given below in kilograms. What is the average weight of the sacks? 49.8, 49.7, 49.5, 49.3, 50,48.9, 49.2, 48.8.
Answer: Solution: Average weight of the sacks \( = \frac{\text{sum of weight of each sack}}{\text{number of sacks}} \)
\( = \frac{49.8+49.7+49.5+49.3+50+48.9+49.2+48.8}{8} \)
\( = \frac{395.2}{8} \)
\( = \frac{3952}{80} \)
\( = 49.4 \)
\( \therefore \) The average weight of the sacks is 49.4 kg.
In simple words: To determine the average weight of the sacks, add up all the individual sack weights and divide by the total number of sacks (8). The average weight is 49.4 kg.

🎯 Exam Tip: Be careful with decimal additions. A small error in summing the numbers can lead to an incorrect average. Ensure the unit (kg) is included in the final answer.

Maharashtra Board Class 7 Maths Chapter 15 Statistics Practice Set 54 Intext Questions and Activities

Question 1. Rutuja practised skipping with a rope all seven days of a week. The number of times she jumped the rope in one minute every day is given below. Find the average number of jumps per minute. 60, 62, 61, 60, 59, 63, 58.
Answer: Solution: Average \( = \frac{\text{Sum of the number of jumps on seven days}}{\text{Total number of days}} \)
\( = \frac{[60]+[62]+[61]+[60]+[59]+[63]+[58]}{7} \)
\( = \frac{423}{7} \)
\( = 60.42 \)
\( \therefore \) Average number of jumps per minute = 60.4
In simple words: To find Rutuja's average jumps per minute, sum her jumps for all seven days and divide by 7. Her average is approximately 60.42 jumps per minute.

🎯 Exam Tip: When calculating averages, double-check that all data points are included in the sum and that the count of data points is accurate for the denominator.