OG 两道数学题，被divide，divisiable, divisor 搞混，求解答！

selenaliu0124

1. A positive integer is divisible by 9 if and only if the sum of its digits is divisible by 9. if n is a positive integer, for which of the following values of k is 25*10ⁿ+k*10²ⁿdivisible by 9?


2. if n is a positive integer and n² is divisible by 72, then the largest positive integer that must divide n is?

豆腐店的86

把答案贴出来看看

1. 2+5+K 整除9
2. n^2整除72  n至少=12 (12^2 = 72x2=144)  一定能被N整除的数是？

A is divisible by B = B divides A  = B is a divisor of A

hope this is helpfu

selenaliu0124

豆腐店的86 发表于 2016-8-14 23:24
把答案贴出来看看

1. 2+5+K 整除9

第一题答案是47，每一一个选项2+5+k可以被9除；
第二题的答案是12。谢谢你的解答！！！多谢多谢！