Question

Average height of 10 students in a class is 150 cm.A boy of height 160 cm left the class and a boy of height 148 cm is admitted

Answer 1

$\huge{\underline{\underline{Question\::-}}}$

Hey mate Your Question is incomplete , The complete Question Should be :-

♦ Average height of 10 students in a class is 150 cm . A boy of height 160 cm left the class and a boy of height 148 cm is admitted, Then find out the new average height of the students .

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$\underline{\underline{Given\::-}}$

• Number of students = 10

• Previous average height = 150 cm

• Height of student left = 160 cm

• Height of student admitted = 148

$\underline{\underline{Solution\::-}}$

♦ Before solving we must know .

• What is Average ?

>> The number obtained by dividing the sum of numbers by number of numbers .

• How to find out Average

>> Average

= $\bold{\dfrac{\sum \: Numbers}{Number\: of \:numbers}}$

♦ Now solving :-

• Let the sum of heights at beginning be "x"

• As Average = $\bold{\frac{\sum \: Numbers}{Number\: of \:numbers}}$

>> Then by replacing values

=> $\bold{\dfrac{ x }{ 10 }}$ = 150

=> x = 10 × 150

=> x = 1500

• Then Sum of heights at beginning = 1500 cm

• Now subtracting the height of student left

= 1500 - 160

= 1340 cm

• Now adding the height of student admitted

= 1340 + 148

= 1488 cm

• Now finding out the new average height of the students

Average height = $\bold{\frac{\sum \: Height}{Number\: of \: Students}}$

= $\bold{\dfrac{1488}{ 10}}$

= 148.8 cm

• So new average height = 148.8 cm