answer
82
steps
put data in numerical order
55, 56, 57, 58, 59, 60, 60, 61, 63, 65, 69, 71, 78, 78, 79, 79, 82, 82, 83, 83
there are 20 numbers = 20
85 is the percentile = p
percentile rank formula
PR = (p/100) * (n + 1)
PR = (85/100) * (20 + 1) = 17.85
round up 17.85 to 18
it's the 18th number which is
82
chatgpt