NCERT 2022 | रेशो से वस्त्र तक - L3| From fiber to fabric | CLASS7 विज्ञान | 8PM Class by Amba Ma'am

A train starts from A at 6 AM and reaches B at 11 AM on the same day. Another train starts from B at 8 AM and reaches A at 3 PM on the same day. At what time the two trains will have crossed each other? एक ट्रेन सुबह 6 बजे शुरू होती है और उसी दिन सुबह 11 बजे B पर पहुंचती है। एक अन्य ट्रेन B से सुबह 8 बजे शुरू होती है और उसी दिन दोपहर 3 बजे A पहुंचती है। किस समय पर दोनों ट्रेनें एक-दूसरे को पार कर लेगी ?

The train ticket fare from places A to B in 2nd class AC and 3rd class AC is Rs.2,500 and Rs.2,000, respectively. If the fares of 2nd class AC and 3rd class AC are increased by 20% and 10%, respectively, then find the ratio of the new fares of 2nd class AC and 3rd class AC. स्थान A से स्थान B तक रेलगाड़ी का द्वितीय श्रेणी ए.सी. और तृतीय श्रेणी ए.सी. का किराया क्रमशः रु.2,500 और रु.2,000 है। यदि द्वितीय श्रेणी ए.सी और तृतीय श्रेणी ए.सी. के किराए में क्रमशः 20% और 10% की वृद्धि हो जाए, तो द्वितीय श्रेणी एसी. और तृतीय श्रेणी ए.सी. के नए किराए का अनुपात ज्ञात कीजिए।

Each of the questions below consists of a question and two statements numbered I and II given below it. You have to decide whether the data provided in the statements are sufficient to answer the question. Read both the statements and give answer 1) if the data in statement I alone are sufficient to answer the question while the data in statement II alone are not sufficient to answer the question. 2) if the data in statement II alone are sufficient to answer the question while the data in statement I alone are not sufficient to answer the question. 3) if the data either in statement I alone or in statement II alone are sufficient to answer the question. 4) if the data even in both statements I and II together are not sufficient to answer the question. 5) if the data in both statements I and II together are necessary to answer the question. What is Kumud’s rank in a class of 40? I. Seema, who is 8th from the top in the class, is above Kailash by 18 ranks, who is below Kumud by 7 ranks. II. Nandini, who is between Kumud and Kishori, is 20th from the bottom.

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?

A company manufactures car batteries of a particular type. The lives (in years) of 40 such batteries were recorded as follows: 2.6 3.0 3.7 3.2 2.2 4.1 3.5 4.5 3.5 2.3 3.2 3.4 3.8 3.2 4.6 3.7 2.5 4.4 3.4 3.3 2.9 3.0 4.3 2.8 3.5 3.2 3.9 3.2 3.2 3.1 3.7 3.4 4.6 3.8 3.2 2.6 3.5 4.2 2.9 3.6 Construct a grouped frequency distribution table for this data, using class intervals of size 0.5 starting from the interval 2 - 2.5.

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 two given expressions on both sides of the ‘=’ sign will have the same value if two numbers from either side or both sides are interchanged .Select the correct numbers to be interchanged from the given options. ‘=’ के दोनों तरफ दिए गए समीकरणों का मान समान होगा यदि किसी भी तरफ या दोनों तरफ की दो संख्याओं को आपस में बदल दिया जाए | दिए गए विकल्पों में से सही संख्याओं का चयन कीजिए जिन्हें आपस में बदला जा सकता है | 4 + 6 xx 7 - 27 div 3 = 7 xx 8 - 4 + 39 div 3

Ravi is 7 ranks ahead of sumit in a class of 39. If Sumit's rank is seventeenth from the last, what is Ravi's rank from the start? 1) 14th 2) 15th 3) 16th 4) 17th 5) None of these

Find the mean deviation from the mean for the following data: Classes 0-100 100-200 200-300 300-400 400-500 500-600 600-700 700-800 Frequencies 4 8 9 10 7 5 4 3