Answer:
. 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.
.
Rewrite to obtain:
.
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:
.
Solve this equation for
to obtain:
.
.
.
In other words, the number of girls here is
.
Answer:
Karen needs to spend $4.5 to buy new hair bands.
Step-by-step explanation:
Given:
Hair bands Karen have = 3
cost of 8 hair bands = $1
Total Hair bands she require = 39
Hence Number of of new hair bands require = Total Hair bands she require - Hair bands Karen have = 39 -3 = 36
we need to find how much money she need to spend to buy new hair bands.
cost of 8 hair bands = $1
Cost of 36 hair bands = money need to spend on hair bands
By using Unitary method we get;
Money spend on new hair bands = 
Hence,Karen needs to spend $4.5 to buy new hair bands.
Answer:

Step-by-step explanation:

The answer is B.
There are about 391,000 of plants currently known to science.
Hope this helps.