JJ 12/30

wanders

DS: 2^n/3 remainder 1 1) (3)^n = (-3)^n 2). ....

A family earn certain amount X(known) of money last week. The father earn 50% more than his son and 20% more than his wife. Ask how much the father earned that week

sammen

设父亲赚的为a，那么母亲的就是0.8a，儿子的是0.5a，加起来就是X了。