How many positive integers less than or equal to 1000 are common multiples of the three numbers 27,225, and 135?

let's find the LCM of the three:

27 = 3x3x3
225 = 3x3x5x5
135 = 3x3x3x5

LCM = 3x3x3x5x5 = 675
the next one would be 1350, which of course > 1000

so there is only one such number.