Num certo bairro da cidade de Beira após o ciclone Idai, 120 voluntários trabalhavam de manhã, 130 trabalhavam à tarde, 80 trabalhavam à noite, 60 trabalhavam de manhã e a tarde, 50 trabalhavam de manhã e a noite, 40 trabalhavam à tarde e a noite e 20 trabalhavam nos três períodos. (a) Quantos voluntários trabalhavam em 2 períodos? (b) Quantos voluntários tem o bairro? (c) Quantos voluntários não trabalhavam á tarde? (d) Quantos voluntários trabalhavam só de manhã?

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

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Titus works at a hotel. part of his job is to keep the complimentary pitcher of water at least half full and always with ice. when he starts his shift, the water level shows 4 gallons, or 128 cups of water. as the shift progresses, he records the level of the water every 10 minutes. after 2 hours, he uses a regression calculator to compute an equation for the decrease in water. his equation is w –0.414t + 129.549, where t is the number of minutes and w is the level of water. according to the equation, after about how many minutes would the water level be less than or equal to 64 cups?