PLEASE HELP MEE!! Shawntae has 21 coins, a combination of nickels and dimes. The total value of her coins is $1.70.
How many of each coin does Shawntae have?
a. Define the variables and then write a system of equations that represent the situation.
(2 points)
b. Solve the system using either the substitution or elimination method. Show your work.
2 points)
C. In a complete sentence, how many nickels and how many dimes does Shawntae have?
(2 points)

The weibull distribution is widely used in statistical problems relating to aging of solid insulating materials subjected to aging and stress. use this distribution as a model for time (in hours) to failure of solid insulating specimens subjected to ac voltage. the values of the parameters depend on the voltage and temperature; suppose α = 2.5 and β = 190. (a) what is the probability that a specimen's lifetime is at most 250? less than 250? more than 300? (round your answers to four decimal places.) at most 250 less than 250 more than 300 (b) what is the probability that a specimen's lifetime is between 100 and 250? (round your answer to four decimal places.) (c) what value is such that exactly 50% of all specimens have lifetimes exceeding that value? (round your answer to three decimal places.) hr