The average heights of x number of girls and 15 boys is 123. if the average heights of boys is 125 and that of girls is 120.find number of girls.

. In other words, there number of girls is .

Step-by-step explanation:

The average of a number of measurements is equal to the sum of these measurements over the number of measurements.

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Rewrite to obtain:

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For this question:

.

.

Therefore:

.

On the other hand, there are boys and girls in total. Using the formula for average:

.

From the question, this average should be equal to . In other words:

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Solve this equation for to obtain:

.

.

.

In other words, the number of girls here is .

no he doesnt because "-16' is negatiive

step-by-step explanation:

the system of inequalities is

step-by-step explanation:

step 1

find the equation of the dashed line

we have the points

(0,0) and (3,1)

the line passes through the origin, so, is a direct variation

find the slope

the equation of the dashed line is

the solution of the inequality a s the shaded area above the dashed line

therefore

the equation of the inequality a is

step 2

find the equation of the solid line

we have the points

(4,0) and (0,4)

find the slope

the equation of the solid line is

the solution of the inequality b s the shaded area below the solid line

therefore

the equation of the inequality b is

step 3

the system of inequalities is