Which system of equations models the following problem if x represents the number of parrotfish Jenna bought and y represents the number of triggerfish she bought? Jenna bought 280 tropical fish for a museum display. She bought 4 times as many triggerfish as parrotfish. How many of each type of fish did she buy?

{x+4y=280y=4x
{x+y=280y=4x
{x+y=4y=280x
{x−y=280y=4x

Aresearch group wants to find the opinions’ of city residents on the construction of a new downtown parking garage. what is the population of the survey downtown shoppers downtown visitors downtown workers city residents

Acell phone company offers two plans to its subscribers. at the time new subscribers sign up, they are asked to provide some demographic information. the mean yearly income for a sample of 40 subscribers to plan a is $45,000 with a standard deviation of $9,200. for a sample of 25 subscribers to plan b, the mean income is $64,300 with a standard deviation of $7,100. at the 0.025 significance level, is it reasonable to conclude the mean income of those selecting plan b is larger? assume unequal population standard deviations. hint: for the calculations, assume the plan a as the first sample. what is the decision rule? (negative amount should be indicated by a minus sign. round your answer to 3 decimal places.) compute the value of the test statistic. (negative amount should be indicated by a minus sign. round your answer to 2 decimal places.) what is your decision regarding h0 ? reject h0 fail to reject h0 compute the p-value. less than 0.01 between 0.01 and 0.025 between 0.025 and 0.05 between 0.05 and 0.10 greater than 0.10

How many times larger is 9 × 10^8 than 3 × 10^-5? a. 3 × 10^13 b. 3 × 10^-40 c. 3 × 10^-13 d. 3 × 10^3