Question 1031260
<pre>
Get the prime factorizations of all three numbers
HCF = 145 = 5*29
LCM = 2175 = 3*5*5*29
one number = 725 = 5*5*29

The other number must contain a factor of 3 for 2175 to be the LCM.
The other number must contain factors 5 and 29 for 145 to be the HCF.
So the other number is 3*5*29 = 435

Edwin</pre>