Let A, B & C be the sets of numbers divisible by 10,15 & 25 respectively No. divisible by 10=100=n(A) No. divisible by 15=66=n(B) No. divisible by 25=40=n(C) No. divisible by (10&15)=33=n(A∩B) No. divisible by (15&25)=13=n(B∩C) No. divisible by (25&10)=20=n(A∩C) No. divisible by (10,15&25)=6=n(A∩B∩C) No. divisible by 10,15and25=n(A∪B∪C)
=100+66+40−33−13−20+6=146
Thus, no. which are neither divisible by 10 nor 15 nor 25=1000−146=854