Answer:
0.13% of students have scored less than 45 points
Step-by-step explanation:
Problems of normally distributed samples can be 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:

About what percent of students have scored less than 45 points?
This is the pvalue of Z when X = 45. So



has a pvalue of 0.0013
0.13% of students have scored less than 45 points
The answer would be 0.10714 or 3/28 if you wanted to simplify it.
Simplest Radical Form. ... Expressing in simplest radical form just means simplifying a radical so that there are no more square roots, cube roots, 4th roots, etc left to find. It also means removing any radicals in the denominator of a fraction.
1 litre of 10% solution contains 100mL of iodine
1 litre of 90% solution contains 900mL of iodine
Mixing them will produce 2 litres of solution containing 1000mL of iodine which is 50% iodine.
To produce 8 litres of 50% iodine they can mix 4 litres of 10% and 4 litres of 90%
We have that
47 ml
we know that
1 lt------------> 1000 ml
X lt -------------> 47 ml
X=47/1000--------> x=0.047 lt
the answer is the option
D: 0.047 L