Y= 4 because when a number is put next to a letter is usally means times/multiply so 7x4= 28
Using the mean concept, it is found that we will need 15 more points to bring up his average up to 90%.
The mean of a data-set is the <u>sum of all observations divided by the number of observations</u>.
In this problem:
- In the first 5 observations, total of 21 out of 25 points, hence the mean for these observations is
. - In the next n observations, mean of 1.
Hence, the mean is:

We want the mean to be of 0.9, thus:





3 more testes are need, each worth 5 points, hence, 15 more points are needed to bring up his average up to 90%.
A similar problem is given at brainly.com/question/25323941
A - 32,500
B- 0.00604
C-2.4x10 to the power of 6
D-1.47x10 to the power of -3
Answer: it’s the third one
Step-by-step explanation:
It is