费费数学六-6

longxiaomeim

看了讨论帖也不大明白:
6、If x and y are integers and xy<>0, what is the remainder when x is divided by y?
(1) when x is divided by 2y, the remainder is 4;
(2) when x+y is divided by y, the remainder is 4;
(1):设A为余数 X=2Y*A+4 X/Y=2A+4/Y 此时要由Y取值来定

(2):设余为B X=(B-1)*Y+4 X/Y=(B-1)+4/Y 此时也需要Y的值才能确定啊 和(1)一样...不明白为什么选B?

longxiaomeim

谢谢,但我上面写的式子有问题吗?

X/Y=(B-1)+4/Y:从这个式子来看却要由Y来确定.

michellemove

2）（X+Y）/Y=X/Y+1，当然和X/Y的余数是一样的。