问一道题：NO.PZ2016012101000100 [ CFA I ]

NO.PZ2016012101000100 问题如下 Purple Fleur S.A., a retailer of florprocts, reportecost of goo solfor the yeof $75 million. Totassets increase$55 million, but inventory cline$6 million. Totliabilities increase$45 million, anaccounts payable increase$2 million.The cash paithe company to its suppliers is most likely closest to: A.$67 million. B.$79 million. C.$83 million. is correct.Cost of goo solof $75 million less the crease in inventory of $6 million equals purchases from suppliers of $69 million. The increase in accounts payable of $2 million means ththe company pai$67 million in cash ($69 million minus $2 million).解析考点是直接法下cash paito suppliers的计算。由于是现金流的流出所以我们都在前面加一个负号，- Cash paito suppliers= - COGS –Δinv + ΔA/P + preciation incluin COGS，本题没有preciation incluin COGS，所以- Cash paito suppliers= - COGS –Δinv + ΔA/P=－75－（-6）+2=－67，负号代表是流出，所以付给供应商的钱是67块。 Inv0+purchase-COGS=Inv1带入之后purchase=69，然后再用69减去2=67如果正确的话，我为什么会正确呢如果不正确的话，这种思路错在哪里呢

NO.PZ2016012101000100 $79 million. $83 million. A  is correct. Cost of goo solof $75 million less the crease in inventory of $6 million equals purchases from suppliers of $69 million. The increase in accounts payable of $2 million means ththe company pai$67 million in cash ($69 million minus $2 million). 解析考点是直接法下cash paito suppliers的计算。由于是现金流的流出所以我们都在前面加一个负号，- Cash paito suppliers= - COGS –Δinv + ΔA/P + preciation incluin COGS，本题没有preciation incluin COGS，所以- Cash paito suppliers= - COGS –Δinv + ΔA/P=－75－（-6）+2=－67，负号代表是流出，所以付给供应商的钱是67块。 ​把数值带入公式这里都没有疑问。只是题目中说存货下降了6，如果存货的成本不变，就说明不仅今年的purchase都卖完了，还消耗了去年的存货？如果问题严格限定为今年向供应商支付的现金流是多少？是不是带入公式的时候就用不考虑“-△inv”这一项了？

totassets totliability的变化量是干扰信息吗？做题的时候该用怎样的思路来识别判断呢？