A bus traveled from the city A to the city B, which was 100 km away. Because of bad weather it moved 10 km/hour slower than it was scheduled and that's why it was late for 30 minutes. What was it's scheduled rate?

Solve the problem by using a venn diagram a group of students were surveyed about their taste in music.they were asked how they like three types of music: rock, country western and jazz.the results are summarized below: no one dislikes all three types of music.six like all three types of music.eleven don’t like country western.sixteen like jazz.three like country western and jazz, but not rock.six don’t like rock.eight like rock and country western.seven don’t like jazz.how many students were surveyed?