Question

find the smallest number that is divided by 21,28and 42​

Answer 1

Answer:

Q.What is the smallest number which when divided by 21, 28, 36 and 45 leaves a remainder of 9?9

Answer:- But if we take as granted that the divisors must be smaller than the divisitor then:

First you find the smallest number that can be divided by 21, 28, 36 and 45.

21: 3×7

28: 2²×7

36: 2²x3²

45: 3²×5

or

21 28 36 45 |2

21 14 18 45 |2

21 7 9 45 |3

7 7 3 15 |3

7 7 1 5 |5

7 7 1 1 |7

1 1 1 1

You conclude on this: 2²×3²×5×7=1260

Then you just add 9 to the number you found: 1269.