The ratio of the number of hours it takes the three pipes a, b and c to fill an olympic pool is 4: 9: 12. answer each of the following questions if it is known that the second pipe takes 72 hours to fill the pool.
b
how long would it take to fill the pool if pipes a and c work to fill the pool and pipe b drains the pool at the same rate as it would be filling it?

Agrain trader buys the following amounts from three suppliers: 3,200 pounds, 5,100 pounds and 700 pounds. what is the total weight of his purchase?

Sue's average score for three bowling games was 162. in the second game, sue scored 10 less than in the first game. in the third game, she scored 13 less than in the second game. what was her score in the first game?

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