Keith bought four new baseball trading cards to add to his collection. The next day his dog ate half of his collection. There are now only thirty - seven cards left. How many cards did Keith start with?

From the beginning of the day the temperature rose 15 degrees so that by 4 pm it was 87 degrees. what was the temperature at the start of the day

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

The interior angles formed by the sides of a hexagon have measures that sum to 720°. what is the measure of angle a? enter your answer in the box. m∠a= °