a is less than 75. the number has 12 and 5 as factors. find the number show how you found it

Question

What is the number that is less than 75

Answer 1

12 and 5 have no common factors except the number 1

12*5=60 (answer)

Answer 2

Hi Emma, if a is less than 75 and has 5 as one of the factors, the number must end in 0 or 5. Example, 70, ends in 0.

 

To have a factor of 12, the number must be even, it cannot be odd. Example: 69, cannot have even factors.

 

That leaves the following possible numbers:

 

70 

1 and 70

2 and 35

5 and 14

 

Not a good number

 

65

Cannot have an even factor

 

Not a good number

 

60

1 and 60

2 and 30

3 and 20

4 and 15

5 and 12

 

Answer: a = 60

 

Questions?