Jennifer had $24 to spend one five pens. after buying them she had $14. how much did each pen cost?

Acollection of coins has value of 64 cents. there are two more nickels than dimes and three times as many pennies as dimes in this collection. how many of each kind of coin are in the collection?

Mr. vector door is buying two new cowboy hats all together the hats cost $75.12 the second heart cost twice as much as the first hat what is the price of the more expensive at round to the nearest hundredth

Agroup of student volunteers participates in a study designed to assess several behavioral interventions for improving output in a repetitive task. prior to the beginning of the study, all volunteers unknowingly observed, and their output is measured. at the beginning of the study, prior to any intervention, the volunteers perform the same task under the observation of a study administrator, and their overall output increases. which of the following terms describes this phenomenon? a. simpson's paradox b. hawthorne effect are d. novelty effect d. pygmalion effect e. observer-expectancy effect