[求助]新手求援...補習班講義一題!

andy7788

Arabian coffee bean costs twice as much as Columbian coffee bean.
A certain store mixes the house blend with 1/4 Arabian and 3/4 Columbian.
What fraction of the cost of the mix is due to the Arabian?

A.1/3 b.1/2 c.2/5 d.3/5 e.3/4

answer is c

我比較笨所以要更努力;因為沒人可以問所以很感謝大家的幫忙...>"<

rabbit

A的价格是B的两倍。一个商店把1/4的A和3/4的B混在一起，其中A占总成本的比例是多少？

（1/4）/（1/4+3/4*1/2）=2/5

Maggieyin

agree with rabbit.