which situation best represent a proportional relationship

kelly sold 2 rings for $3 and 3 rings for $6
lawrence packed 27 plates in 9 boxes and 81 plates in 27 boxes
jeff ran 4 miles in 20 minutes and 6 miles in 24 minutes.
francesca placed 8 pencils in 2 cases and 16 pencils in 8 cases.

Give the equations of two different lines that are perpendicular to the line 3x + 4y = 7.

Since opening night, attendance at play a has increased steadily, while attendance at play b first rose and then fell. equations modeling the daily attendance y at each play are shown below, where x is the number of days since opening night. on what day(s) was the attendance the same at both plays? what was the attendance? play a: y = 8x + 191 play b: y = -x^2 + 26x + 126 a. the attendance was never the same at both plays. b. the attendance was the same on day 5. the attendance was 231 at both plays on that day. c. the attendance was the same on day 13. the attendance was 295 at both plays on that day. d. the attendance was the same on days 5 and 13. the attendance at both plays on those days was 231 and 295 respectively.

Carl's candies has determined that a candy bar measuring 3 inches long has a z-score of +1 and a candy bar measuring 3.75 inches long has a z-score of +2. what is the standard deviation of the length of candy bars produced at carl's candies?