Mathematics made clear

  RD Sharma Solutions For Class 7 Chapter 24 – Data Handling – III (Constructions of Bar graphs) 1. Two hundred students of class VI and VII were asked to name their favorite colours so as to decide upon what should be the colour of their school house. The results are shown in the following table. Colour: Red Green Blue Yellow Orange Number of Students 43 19 55 49 34 Represent the given data on a bar graph. (i) Which is the most preferred colour and which is the least? (ii) How many colours are there in all? Solution: Steps of constructing bar graph: 1. Mark the horizontal axis OX as Name of the Colour and the vertical axis OY as Number of Students. 2. Along the horizontal axis OX, choose bars of uniform (equal) width, with a uniform gap between them. 3. Choose a suitable scale to determine the heights of the bars, according to the space available for the graph. Here, we choose 1 small division to represent 10 students. (i) The most preferred colour is blue and the least preferred ...

  RD Sharma Solutions For Class 7 Chapter 25 – Data Handling – IV (Probability) 1. A coin is tossed 1000 times with the following frequencies: Head: 445, Tail: 555 When a coin is tossed at random, what is the probability of getting? (i) A head? (ii) A tail? Solution: Given total number of times a coin is tossed = 1000 Number of times a head comes up = 445 Number of times a tail comes up = 555 (i) Probability of getting head = number of heads/total number of trails = (445/1000) = 0.445 (ii) Probability of getting tail = number of tail/total number of trails = (555/1000) = 0.555 2. A die is thrown 100 times and outcomes are noted as given below: Outcome 1 2 3 4 5 6 Frequency 21 9 14 23 18 15 If a die is thrown at random, find the probability of getting a/an: (i) 3 (ii) 5 (iii) 4 (iv) Even number (v) Odd number (vi) Number less than 3. Solution: Given total number of trials = 100 (i) From the table, number of times 3 comes up = 14 Probability of getting 3 = frequency of 3/ total numbe...