homework help for pre algebra

Question

Jon tried to shade only composite numbers on the hundred chart.

What mistake did Jon make?

Jon tried to shade only composite numbers on the hundred charts number are 1 to 100. the shaded numbers should be 51,65,84

Choose 1 answer:

1. (Choice A)
2. A
3. Jon is correct.
4. (Choice B)
5. B
6. 51is prime, not composite.
7. (Choice C)
8. C
9. 65 is prime, not composite.
10. (Choice D)
11. D
12. 84 is prime, not composite.

Answer 1

A is correct

51, 65, 84 are not prime

51=3(17)

65 =5(13)

84=3(2)(2)(7)

if any number ends in 5, it's divisible by 6

if the digits sum to a number divisible by 3, the number is divisible by 3

5+1 = 6. 6 is divisible by 3

8+4=12 1+2 =3 3 is divisible by 3