Question

find the least square number exactly divisible by each one of the number 6,9,10,15 and 20

Answer 1

Answer:

900

Step-by-step explanation:

LCM of 6,9,10,15,20 = 180

Since the square number is divisible by 6,9,10,15,20, it is divisible by 180 also.

180 = 2^2 × 3^2 × 5

Hence, 5 is the least number to be multiplied to 180 to make it a perfect square.

Therefore, answer = 180 × 5 = 900

Answer 2

Answer:

Step-by-step explanation:

ok if this helps

Divisibility by 6: The number should be divisible by both 2  and 3.

Divisibility by 9: The sum of digits of the number must be divisible

by 9.

Divisibility by 10: The number should have 0 as the units digit.

Divisibility by 15: To be divisible by 15 a number has to be divisible by 3 and by 5. To be divisible by 5 the number must end in a 0 or a 5, easy enough. However divisibility by 3 is not so simple - the rule is to add up all of the digits of the number and if they are a multiple of 3 then the original number is also.

Divisibility by 20: It is divisible by 10, and the tens digit is even.

so it has to end it a 0.

100

400

900

1600

2500

the tens digit has to be even because of the 20 but 0 is even

the sum of the digits has to be divisible by 9

900

that leaves 900 as the answer