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Tamil Nadu Board of Secondary EducationSSLC (English Medium) Class 7

The mean height of 11 students in a group is 150 cm. The heights of the students are 154 cm, 145 cm, Y cm, Y + 4 cm, 160 cm, 151 cm, 149 cm, 149 cm, 150 cm, 144 cm and 140 cm. - Mathematics

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Question

The mean height of 11 students in a group is 150 cm. The heights of the students are 154 cm, 145 cm, Y cm, Y + 4 cm, 160 cm, 151 cm, 149 cm, 149 cm, 150 cm, 144 cm and 140 cm. Find the value of Y and the heights of two students?

Sum

Solution

Mean Height = `"Sum of heights of all students"/"Number of students"`

150 = `(154 + 145 + "Y" + ("Y" + 4) + 160 + 151 + 149 + 149 + 150 + 144 + 140)/11`

150 = `(1342 + "Y" + "Y" + 4)/11`

150 = `(1346 + 2"Y")/11`

150 × 11 = 1346 + 2Y

1650 = 1346 + 2Y

2Y = 1650 – 1346 = 304

Y = `304/2` = 152

Height of two students are Y and Y + 4

⇒ 152 and 152 + 4

⇒ 152 cm and 156 cm

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Chapter 5: Statistics - Exercise 5.1 [Page 100]

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Samacheer Kalvi Mathematics - Term 3 [English] Class 7 TN Board
Chapter 5 Statistics
Exercise 5.1 | Q 4 | Page 100
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