问一道题：NO.PZ2019070901000094 [ FRM II ]

NO.PZ2019070901000094 问题如下 Whiof the following statements about the capitconservation buffer are TRUE?I. It is meant to protebanks in times of financistress.II. It means thin normtimes a bank shoulhave a minimum 7% Tier 1 equity capitratio, totcapitmust 10.5% of risk-weighteassets in normperio.III. It cset between 0.0% an2.5% of risk-weighteassets the regulators in invicountries. A.only I. B.only II. C.I anII. I, II anIII. C is correct. 考点the capitconservation buffer解析The capitconservation buffer旨在金融危机时保护银行, I 正确。正常情况下，对于Tier 1 equity capital，银行必须建立2.5%的buffer来cover银行在金融危机时的损失，即在正常情况下，Tier 1 equity capital的最低要求为7%（4.5%+2.5%=7%），totTier 1 capital为8.5%，Tier 1和Tier 2为10.5%。II 正确。The capitconservation buffer是监管要求，不是由各国的监管机构自行决定的，III 错误。 老师在tier 1 capital当中，有个核心资本core tier 1 capit，是不是也叫euqity tier 1 capital

NO.PZ2019070901000094 问题如下 Whiof the following statements about the capitconservation buffer are TRUE?I. It is meant to protebanks in times of financistress.II. It means thin normtimes a bank shoulhave a minimum 7% Tier 1 equity capitratio, totcapitmust 10.5% of risk-weighteassets in normperio.III. It cset between 0.0% an2.5% of risk-weighteassets the regulators in invicountries. A.only I. B.only II. C.I anII. I, II anIII. C is correct. 考点the capitconservation buffer解析The capitconservation buffer旨在金融危机时保护银行, I 正确。正常情况下，对于Tier 1 equity capital，银行必须建立2.5%的buffer来cover银行在金融危机时的损失，即在正常情况下，Tier 1 equity capital的最低要求为7%（4.5%+2.5%=7%），totTier 1 capital为8.5%，Tier 1和Tier 2为10.5%。II 正确。The capitconservation buffer是监管要求，不是由各国的监管机构自行决定的，III 错误。 老师这个表述三如果改成是监管的要求而不是各个国家制定的，那表述三对吗？因为我觉得讲义直接给了确定的2.5%，这里写的是0-2.5%，即便改成监管要求是不是也不对啊

请问 tottier 1capit为8.5%，怎么计算出来的呢？