Please help explanation if possible

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

Question 3(multiple choice worth 1 points) use the arc length formula and the given information to find r. s = 16 cm, θ = 48°; r = ? sixty divided by pi cm thirty divided by pi cm one third cm one hundred twenty divided by pi cm

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?