Question

What is the least number which when decreased by 7 is exactly divisible by 12,

16, 18, 21 and 28


a) 1022
b) 1015
c) 1012
d) 1008​

Answer 1

Answer:

your answer

Step-by-step explanation:

First find the smallest number divisible by 12,16,18,21 and 28. It is the LCM of these numbers. So the number will be 1008+7 = 1015. So the required number is 1015.

Answer 2

Hey Mate!!

Let the number be "X"

X-7 = divisible by 12

Let us assume the number is xSo x-7 is divisible by 12,16,18,21 and 28(x-7) is the LCM of the following numbers: i.e. 1008x-7=1008x=1015

|2 12, 16, 18, 21, 28

|7 6, 8, 9, 21, 14

|3 6, 8, 9, 3, 2

|2 2, 8, 3, 1, 2

| 1, 4, 3, 1, 1

LCM=273243=1008LCM=273243=1008

Required number =1008+7=1015=1008+7=1015.

Option b is correct!!

Hope this helps you!!