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Junior high school mathematics olympiad clock questions and answers
A wall clock, 5 minutes slow every hour, at noon of standard time 12, set the clock to standard time. It's 5: 30 pm standard time. How long will it take for the wall clock to go to 5: 30 pm?

Analysis: 1, this clock is 5 minutes slow every hour, that is, when the standard clock runs for 60 minutes, this wall clock can only run for 60-5=55 minutes, that is, the speed is ` = of the standard clock speed.

2. Because the standard clock moves from noon 12 to 5: 30 pm, the wall clock * * * is 5×( 17- 12)=27 (minutes), that is, the difference is 27 minutes to 5: 30.

This wall clock goes at 5: 30, and it goes for 27 minutes according to the standard time. Because its speed is the standard clock speed, the actual time to complete these 27 minutes should be 27 minutes.

Solution: 5×( 17- 12) =27 (minutes) 27÷30 (minutes).

A: It will take another 30 minutes for the wall clock to go to 5: 30.