单选题

单选题 According to the survey data, on average, how many hours will a typical teenager spend watching television and sleeping in one year?

A、 1,460 hours
B、 2,555 hours
C、 3,650 hours
D、 4,015 hours
E、 (E) 4,745 hours

【正确答案】 E

【答案解析】The first step in solving this problem is to recall that there are 365 days in a typical year and 24 hours in one day. Therefore, a teenager will spend a total of 365×24=8,760 hours on all activities in one year. Next, notice that in one day, a teenager spends 3 hours watching TV and 10 hours sleeping; therefore, 13 out of 24 hours are spent on those two activities. Set up a proportion to solve:
[*]
113,880=24x
4,745=x

单选题 Which of the following represents the ratio of the hours teenagers spend on Work/School to the hours teenagers spend on all activities?

A、 17:24
B、 7:17
C、 7:24
D、 24:17
E、 (E) 24:7

【正确答案】 C

【答案解析】To solve this problem, look at the graph to see that teens spend 7 hours per day on Work/School. Therefore, the ratio is [*] or 7:24.