Question

Find the least number which on decreasing by 20 is exactly divisible by all the numbers-
18, 21, 28 and 30

Answer 1

Answer:

Here's your answer

First , we find the least number which is exactly divisible by the numbers 18,21,28 and 30 . For this , we find the L.C.M of 18,21,28 and 30.

∴ L.C.M =2×2×3×3×5×7=1260

According to given , the required will be 20 more than 1260.

The required number =1260+20=1280