题库搜索>问题求解PS-12205
If n is the product of the integers from 1 to 20 inclusive, what is the greatest integer k for which 2k is a factor of n?
分析A选项
分析B选项
分析C选项
分析D选项
分析E选项
1到20中因数里含有2的数有2、4、6、8、10、12、14、16、18、20十个数字。
其中,2、6、10、14、18中只有一个2(2=2*1,6=2*3等),这几个数字中共有5个2.
在4和12、20中分别含有2的平方(4=2的平方,12=2的平方*3等),共有6个2.
8=2的三次方,则8含有3个2.
同理,16=2的四次方,16中有4个2.
所以含2的数字的总共有5+6+3+4=18个
默默
做这种题的步骤: 1,找出有幂值因子的数 2,再看看他们到底能包含几个幂
默默回复默默
再将个数相加
0
0
回复
2018-04-22 13:57:28
mmxx
1*2*3*···*19*20 ,求有几个2相乘
科目:
问题求解PS
来源:
GWD
2m26s
平均耗时
79.3%
平均正确率
该题由网友qAiUdPG提供
点击上传问题求解PS -17894
An 〝Armstrong number〞is an n-digit number that is equal to the sum of the nth powers ofits individual digits. For example, 153 is an Armstrong number because it has 3 digits and 13+53+33 =153 .What is the digit k in the Armstrong number 1, 6k 4?
问题求解PS -17869
Of the following, which is greatest?
问题求解PS -17767
Let n and k be positive integers with k≦n. From an n×n array of dots, a k×k array of dots is selected. The figure above shows two examples where the selected k×k array is enclosed in a square. How many pairs (n, k) are possible so that exactly 48 of the dots in the n×n...
问题求解PS -17497
What is the smallest integer n for which ?
问题求解PS -17457
If p is the product of the integers from 1 to 30, inclusive, what is the greatest integer k for which 3k is a factor of p ?
问题求解PS -17894
An 〝Armstrong number〞is an n-digit number that is equal to the sum of the nth powers ofits individual digits. For example, 153 is an Armstrong number because it has 3 digits and 13+53+33 =153 .What is the digit k in the Armstrong number 1, 6k 4?
问题求解PS -17869
Of the following, which is greatest?
问题求解PS -17767
Let n and k be positive integers with k≦n. From an n×n array of dots, a k×k array of dots is selected. The figure above shows two examples where the selected k×k array is enclosed in a square. How many pairs (n, k) are possible so that exactly 48 of the dots in the n×n...
问题求解PS -17497
What is the smallest integer n for which ?
问题求解PS -17457
If p is the product of the integers from 1 to 30, inclusive, what is the greatest integer k for which 3k is a factor of p ?