求救：一道prep数学题DS

When positive integer n is divided by 3, the remainder is 2; and when positive integer t is divided by 5, the remainder is 3. What is the remainder when the product nt is divided by 15?

(1)n-2 is divisible by 5

(2)t is divisible by 3

不好意思，算错了

Ｃ各～

题目中条件n=3A+2  t=5B+3

由条件１得，n=5C+2. 又n=3A+2　　所以Ａ＝５S,则n=15s+2

由条件２得，t=3D.结合题目条件t=5B+3　　说明Ｂ是３的倍数，即Ｂ＝３k．　则t=１５k+3

单独均不可推，合以来可推　６