数学难题！！！（英文+数学）

from digit number is 3 times the sum of its digits.
we can see that it's a 2 digit number m is十位数 and n is个位数

10m+n=3(m+n)

from second line
we can use the reverse of m&n

10n+m=x(m+n)

then add these two eqn. up

11m+11n=(x+3)(m+n)
11(m+n)=(x+3)(m+n)
11=x+3
x=8

A two-digit number is 3 times the sum of its digits.
If the 2 digits are reversed， the number is x times the sum of its digits.

一个两位数是它每位数之和的三倍。
如调换这个两位数的数字位置，问它是原数每位数之和的多少倍。

答：27=3*(2+7)
72=9x --> x=8

360
=
90*2*2
450
=
90*5
540
=
90*2*3
Least
Common
Multiple
(最小公倍数):
90*2*2*3*5
=
5400
days