In a class of 35 students, 19 take history and 12 take economics. If 5 take both subjects,
how many take neither?​

9

Step-by-step explanation:

If 19 students take history, 12 take economics and 5 take both:

19-5 = 14 students that take only history

12-5 = 7 students that take only economics

Therefore total number of students who either history, economics or history and economics: 14 + 7 + 5 = 26

Therefore students who take neither: 35 - 26 = 9

54 km / hours

step-by-step explanation:

we need to convert seconds to hours

60 seconds = 1 minutes

60 minutes = 1hour

15 m         60 second   60 minutes

  * *         = 54000 meters/ hour

second     1 minute             1 hour

now we need to convert meters to km

1000 m = 1 km

54000 m       1 km

*   = 54 km / hours

hour               1000m