Question

*If the average height of 20 girls in the class is 130 cm and the average height of 20 boys is 134 cm, what is the average height of all the students in the class?
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Answer 1

Answer:

Explanation:

Let the sum of height of 20 girls be x and height of 20 boys be y.

then,

Average=Sum/total no.

Girls:    130=x/20

          ⇒x = 130×20

          ⇒x = 2600

Boys:     134=y/20

           ⇒y = 134×20

           ⇒y = 2680

Next, Total sum of height of boys and girls= 2600+2680

                                                                          =5280

          Total no. of students= 20+20=40

 Thus,

Average= Sum/Total no.

              =5280/40

              =132cm.