iijmio.rkt

#lang racket

(struct plan
  (type
   data-amount
   price)
  #:transparent)

(define plans-voice
  (vector
   (plan 'voice 2 850)
   (plan 'voice 4 990)
   (plan 'voice 8 1500)
   (plan 'voice 15 1800)
   (plan 'voice 20 2000)))

(define plans-esim
  (vector
   (plan 'esim 2 440)
   (plan 'esim 4 660)
   (plan 'esim 8 1100)
   (plan 'esim 15 1430)
   (plan 'esim 20 1650)))

(define plans (vector-append plans-voice plans-esim))

(vector-sort plans <
             #:key (lambda (p)  (/ (plan-data-amount p) (plan-price p))))