SAT数学题求简便算法How many of the positive divisors of 960 are also multiples of 6?A 960 B 160 C 80 D 10 E 12求简便算法，不要一个一个数的，要在考试时可以节省时间的算法，谢谢How many 3-digit numbers between 100 and 200 have a digit that is the average of the other 2 digits?A 10
2019-05-23
SAT数学题求简便算法
How many of the positive divisors of 960 are also multiples of 6?
A 960 B 160 C 80 D 10 E 12
求简便算法，不要一个一个数的，要在考试时可以节省时间的算法，谢谢
How many 3-digit numbers between 100 and 200 have a digit that is the average of the other 2 digits?
A 10 B 6 C 9 D 11 E 20
优质解答
分解质因数960=3×2∧6×5
=6×2∧5×5
很容易有规律的看出
有：6 6×2∧1 6×2∧2 6×2∧3 6×2∧4 6×2∧5
6×5 6×2∧1×5 6×2∧2 ×5 6×2∧3 ×5 6×2∧4×5 6×2∧5×5
共12个
分解质因数960=3×2∧6×5
=6×2∧5×5
很容易有规律的看出
有：6 6×2∧1 6×2∧2 6×2∧3 6×2∧4 6×2∧5
6×5 6×2∧1×5 6×2∧2 ×5 6×2∧3 ×5 6×2∧4×5 6×2∧5×5
共12个