Students

Related Keyword : Students | The average weight of 60 students in a class was calculated to be 40kg. Later it was found out that the weight of one of the students was calculated as 36 kg, whereas his actual weight was 33kg. What is the actual average weight was 33kg. What is the actual average weight of the students in the class? | A class is divided into two sections A and B. passing average of 20 students of section A is 80% and passing average of 30 students of section B is 70%. What is the passing average of both the sections? | CORRECT MEASUREMENT OF LENGTH In our daily life we use various types of measuring devices. We use a metre scale for measuring length. A tailor uses a tape, whereas a cloth merchant use a metre rod. For measuring the length of an object, you much choose a suitable device. You cannot measure the girth of a tree or the size of your chest using a metre scale, for instance. Measuring tape is more suitable for this. For small measurement, such as the length of your pencil, use can use a 15 cm scale from your geometry box. In taking measurement of a length we need to take care of the following: 1. Place the scale in contact with the object along its length. 2. In some scales, the ends may be broken. You may not be able to see the zero mark clearly. In such cases, you should avoid taking measurement from the zero mark of the scale. You can use any other full mark of the scale, say, 1.0 cm. Then you must subtract the reading of this mark from the reading at the other end. For example, the reading at one end is 1.0 cm and the other end it is 14.3 cm. Therefore, the length of the object is (14.3-1.0) cm = 13.3 cm. 3. Correct position of the eyes is also important for taking measurement. Your eyes must be exactly in front of the. Position ‘B’ is the correct position of the eyes. Note that from position ‘B’ the reading is 7.5 cm. From position ‘A’ and ‘C’, the readings may be different. Activity : Measurement the height of your classmate using hand span and then by using a metre scale. For this, ask your classmate to stand with his back against a wall. Make a mark on the wall exactly above his head. Now, measure the distance from the floor to this mark on the wall with your handspan and then with a metre scale. Let all other students measure this length in a similar way. | In a class of 45 students, a boy is ranked 20th. When two boys joined, his rank was dropped by one. What is his new rank from the end ? | A sum of Rs.700 has to be used to give seven cash prizes to the students of a school for their overall academic performance. If each prize is Rs.20 less than its preceding prize, what is the least value of the prize? | The following frequency distribution shows the distance (in meters) thrown by 68 students in a Javelin throw competition | Find the mode of the following distribution of marks obtained by the students in an examination |

 

Find the mode of the following distribution of marks obtained by the students in an examination

Find the mode of the following distribution of marks obtained by the students in an examination:

     

Given the mean of the above distribution is 53, using empirical relationship estimate the value of its median.

     Answer

      

Mode = 68

So, the mode marks is 68.

Empirical relationship between the three measures of central tendencies is:

3 Median = Mode + 2 Mean

3 Median = 68 + 2 × 53

Median = 58 marks


15th April 2019

ncert solution

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The following frequency distribution shows the distance (in meters) thrown by 68 students in a Javelin throw competition

The following frequency distribution shows the distance (in metres) thrown by 68 students in a Javelin throw competition.

Draw a less than type Ogive for the given data and find the median distance thrown using this curve.

Answer

Median distance is value of x that corresponds to

Cumulative frequency N/2 = 68/2 = 34

Therefore, Median distance = 36 m


10th April 2019

ncert solution

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