L.C.M. of 8, 10, 12 = 2 x 2 x 2 x 3 x 5 = 120The largest three digit number = 999Therefore, the required number = 999 – 39 = 960
Number of 4-digit numbers that are less than or equal to 2800 and either divisible by 3 or by 11 , is equal to