The average price for a gallon of gasoline in the United States is $3.73 and in Russia it is $3.40. Assume these averages are the population means in the two countries and that the probability distributions are normally distributed with a standard deviation of $.25 in the United States and a standard deviation of $.20 in Russia.

What percentage of the gas station in Russia charge less than $ 3.50?

69.15% of the gas station in Russia charge less than $ 3.50

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.

What percentage of the gas station in Russia charge less than $ 3.50?

This is the pvalue of Z when

has a pvalue of 0.6915

69.15% of the gas station in Russia charge less than $ 3.50

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.

step-by-step explanation:

mean or average is 40.6