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:

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

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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 .

$54.99

step-by-step explanation:

$54.99 includes 500 min. if she does not exceed 500 min then her bill is $54.99

6^2 or 36

step-by-step explanation:

6000n

6×1000n

6×10^3 n

so we need 6n need to be a perfect cube

so n has to be 6^2 so that 6n is 6^3

what i'm saying is if you let n be 6^2 you have 6^3×10^3 or 60^3 which is a perfect cube