英语翻译
By using a new process the prime cost of the television set was reduced by 3.4 times.
为什么was reduced by 3.4 times 是翻译成“降低了71% ” ,也就是12/17?
The sales of TV set have risen 3.5 fold.
为什么risen 3.5 fold 是翻译成“增加了2倍半”.
我不是讲英文翻译，翻译我懂，就是3.4怎么变成12/17的？3.5怎么变成两倍半？这个我没搞懂。