What will be the least number which when doubled will exactly be divisible by 12, 18, 21 and 30?
630
1260
2520
None of these
L.C.M. of 12, 18, 21, 30 = 2 x 3 x 2 x 3 x 7 x 5 = 1260.
∴ Required number = (1260 / 2) = 630.