Question

The average height of x number of girl and 15 boys is 123cm.if the average height of boys is 125cm. find the number of girls
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Answer 1

Step-by-step explanation:

answer 162

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Answer 2

Answer:

According to ratio , there are 20 boys and 25 girls in the class.

Average height =

sum of height of all students÷ total no. of students

So, 142 = sum of height of all students ÷ 45

Hence, sum of height of all students= 142×45

And,

140= sum of height of all girls ÷ 25

Hence, sum of height of all girls=140× 25

And,

Average height of boys = sum of height of all boys ÷ 20

Hence, sum of height of all boys= avg height of boys × 20

Now,

Sum of height of all students = sum of height of boys + sum of height of girls

142× 45=( 140×25) + (avg height of boys ×20)

Solving the equation , you will get

Avg height of boys = 144.5 cm