请教 Prep Math 的两道题

第一道是说K is a list containing 12 consecutive integers, -4 is the least integer in K, then what is the range of positive integers in K.

我觉得是7，答案说是6。 可是我以为K={-4, -3, -2, .......7} 那应该是7个正整数啊？

第二道说n and y are both positive integers, if 450y=n^3, then which of the following is an integer. 

答案是 Y/(3*5*2^2)

我也不能理解。按照题目，y=n^3 / 450, 带入答案得到 n^3 / (3^3 *5^3 *2^3) = [n/(3*5*2)]^3.  可是没人能保证 n/(3*5*2) 是整数啊？

谁能帮忙解释一下？

The answer of first question is 6, exactly. Zero is neither positive nor negative.

1. cuz the numbers are consecutive, the least one is -4, so it must be

         -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6

  in this way, the range of the positive integers in K= 6-0=6

2.cuz 450y=n^3, we know that the unit of n must be "0" to make this equation,

   just suppose  y=60, n=30, 450*60=27000=30*900

   and take this into every option.

第一题，0不是整数也不是负数7-1=6

第二题，3*5*2^2*450=30^3 y最小等于3*5*2^2 所以y/(3*5*2^2)为整数。