0. 1X+0.5Y+Z=7 ( 1)

X+Y+Z= 15 (2)

X is an integer multiple of 5 (3) (this is easy to understand, money is not an integer unless it is an integer of 5)

According to (1) and (2):

9X+5Y=80

And x can only be an integer multiple of 5.

Then when X=5, Y=7, X= 10 and above, y is negative, then x can only be equal to 5.

Then X=5, Y=7 and Z=3.

So 1.50 1 yuan coins are 5, 7 and 3 respectively.