Answer:
2.28% of tests has scores over 90.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean 
and standard deviation 
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
What proportion of tests has scores over 90?
This proportion is 1 subtracted by the pvalue of Z when X = 90. So
has a pvalue of 0.9772.
So 1-0.9772 = 0.0228 = 2.28% of tests has scores over 90.
0.8
you find how much he needed so:
24*0.3=7.2
than 8 he had , so whats left over
8-7.2=0.8
Answer:
Melanie's account balance now is $3182.87.
Step-by-step explanation:
Given:
Amount of money in her account = $3106.12
Amount deposited on Thursday = $85
Amount spent for lunch on Friday = $8.25
We need to find the remaining balance in Melanie's account.
Solution:
Now we know that;
Remaining balance in her account is equal to Amount of money in her account plus Amount deposited on Thursday minus Amount spent for lunch on Friday.
framing in equation form we get;
Remaining balance in her account = 
Hence Melanie's account balance now is $3182.87.
Answer:
to find compound interest
it is
p(1+r) ^n
p stands for principa
r is the rate (percentage)
n is the amount of years
820(1+3.5 ) ^ 5
100
chsnge the percentsge to a decimal and add it to 1.
820(1 + 0.035) ^ 5
820(1.035)^5
raise what is in the bracket to the power of 5 which is the amount of years
820× 1.19
=£975.80
im not good with simple interest,could someone else show her how to do it please
