A8. When servicing a personal car, the oil needs to be changed every $7500 \mathrm{~km}$, the air filter every $15000 \mathrm{~km}$, the spark plugs every $25000 \mathrm{~km}$, and the brake fluid every $30000 \mathrm{~km}$. After how many kilometers will it first be necessary to replace the oil, air filter, spark plugs, and brake fluid all at the same service?
(A) 60000
(B) 90000
(C) 120000
(D) 150000
(E) 300000
A8 The least common multiple of the numbers 7500, 15000, 25000, and 30000 is 150000.