NCERT 2022 | पौधे एवं जंतुओं का संरक्षण - L5 | CLASS 8 विज्ञान | 7 PM Class by Amba Mam

The average weight of a certain number of students in a class is 68.5 kg. If 4 new students having weights 72.2 kg, 70.8kg, 70.3kg and 66.7 kg join the class, then the average weight of all the students increases by 300 g. The number of students in the class, initially is: किसी कक्षा में छात्रों की एक निश्चित संख्या का औसत वज़न 68.5 किलो ग्राम है | यदि 4 नए छात्र कक्षा में आ जाते हैं, जिनका वज़न क्रमशः 72.2 किलो ग्राम, 70.8 किलो ग्राम, 70.3 किलो ग्राम तथा 66.7 किलो ग्राम है, तो सभी छात्रों का औसत वज़न 300 ग्राम से बढ़ जाता है | आरंभ में कक्षामें छात्रों की संख्या कितनी थी ?

The average weight of some students in a class was 58.4kg. When 5 students having the average weight 62.8 kg joined the class, the average weight of all the students in the class increased by 0.55 kg. The number of students initially in the class were: एक कक्षा में कुछ छात्रों का औसत वज़न 58.4 किलो ग्राम था | जब 62.8 किलो ग्राम औसत वज़न वाले 5 छात्र इस कक्षा में आते हैं, तो कक्षा के सभी छात्रों का औसत वज़न 0.55 किलो ग्राम बढ़ जाता है | आरंभ में कक्षा में छात्रों की संख्या कितनी थी ?

Thirty children were asked about the number of hours they watched TV programmes in the previous week. The results were found as follows: 1 6 2 3 5 12 5 8 4 8 10 3 4 12 2 8 15 1 17 6 3 2 8 5 9 6 8 7 14 12 (i) Make a grouped frequency distribution table for this data, taking class width 5 and one of the class intervals as 5 - 10. (ii) How many children watched television for 15 or more hours a week?

The proportion of the number of students in three classes is 1 : 2 : 3. If 20 students are included in each class, then the proportion becomes 3 : 5 : 7. What was initially the total number of students in the three classes? तीन कक्षाओं में छात्रों की संख्या का अनुपात 1 : 2 : 3 है | यदि प्रत्येक कक्षा में 20 छात्र शामिल कर लिए जाते हैं, तो यह अनुपात 3 : 5: 7 हो जाता है | इन तीन कक्षाओं में आरंभ में कितने छात्र थे?

The distance (in km) of 40 engineers from their residence to their place of work were found as follows: 5 3 10 20 25 11 13 7 12 31 19 10 12 17 18 11 32 17 16 2 7 9 7 8 3 5 12 15 18 3 12 14 2 9 6 15 15 7 6 12 Construct a grouped frequency distribution table with class size 5 for the data given above taking the first interval as 0-5 (5 not included). What main features do you observe from this tabular representation?

The following data : 2, 5, 15, 25, 20, 12, 8, 7, 6, 16, 21,17, 30, 32, 23, 40, 51, 15, 2, 9, 57, 19, 25 is grouped in the classes 0 –5, 5 –10, 10 –15 etc. Find the frequency of the class 20 –25.

Find the median of the following data: class : 0-10 , frequency :5 , 10-20 , 3 , 20-30 , 4 , 30-40 , 3 , 40-50 , 3, 50-60 , 4, 60-70 , 7 , 70-80 , 9 , 80-90 , 7 , 90-100 , 8 ,

the daily minimum temperatures in degrees Celsius recorded in a certain Arctic region are as follows: -12. 5 ,-10. 8 ,-18. 6 ,-8. 4 ,-10. 8 ,-4. 2 ,-4. 8 ,-6. 7 ,-13. 2 , -11. 8 ,-2. 3 , 1.2 , 2.6 ,0,-2. 4 ,0, 3.2 , 2.7 , 3.4 ,0,-2. 4 ,-2. 4 ,0, 3. 2 , 2.7 , 3.4 ,0,-2. 4 ,-5. 8 ,-8. 9 ,-14 ,6,-12. 3 ,-11. 5 ,-7. 8 ,-2. 9 Represent them as frequency distribution table taking -19. 9\ to-15 as the first class interval.