Please Help! Allocated Transaction

Where is the number '101', in the last snapshot, is coming from? Can someone show me the formula to calculate it?

16. Surfside Ltd is marketing a 'surfing bundle' in which, for $1100, it provides customers with a surfboard (which retails separately for $850), a wetsuit (which retails separately for $250) and five lessons (which retail separately for $200). You are required to determine: (a) Whether separate performance obligations exist, and to explain why you made this judgement. (b) How much of the transaction price to allocate to each performance obligation. LO 15.7, 15.8.. Good or service Stand-alone price $850 Surfboard Wetsuit Lessons $250 $200 $1,300 $1,100 At sale (being, first day of the financial year 1 July 2021): 1 July 2021 Cash/Accounts Receivable Dr Liability - surfboard Cr Liability - wetsuit Cr Liability - lessons Cr Assume surfboard and wetsuit is delivered the next day: 2 July 2021 Liability - surfboard Dr Liability-wetsuit Dr Revenue - surfboard Cr Revenue - wetsuit Cr Discount allocation Allocated amount 850/1300 x $200 = $131 $719 250/1300 x $200 = $38 $212 200/1300 x $200 = $31 $169 $200 1 100 719 212 719 212 169 719 212 The undelivered element (i.e. the lessons) will be recognised when those services are delivered. Because the lessons are available to the counterparty continuously over the period of the agreement the revenue should be recognised in accordance with AASB 15/IFRS 15 on a straight-line basis. At the end of the first year (i.e., 30 June 2022) Surfside Ltd has provide three lessons: 30 June 2022 Liability - lessons Dr 101 Revenue lessons Cr 101