They are 165/3-2, 165/3 and 165/3+2 = 53, 55 and 57.
3 hrs, divide 165 by 55
3
165
18 of them
3 pencils for 1.65 implies that pencils are 1.65/3 = 0.55 each. Then 7 are 7*0.55 = 3.85
55
Cause pencils are cool :3
They are 165/3-2, 165/3 and 165/3+2 = 53, 55 and 57.
3 hrs, divide 165 by 55
The prime factors of 165 are 3, 5, 11 165 = 3*5*11
4
5 of the other boxes, 3 contain only red pencils, 1 contains only black pencils, and 3 contain mixed pencils. I came to this answer with this formula: x=12- [(6-3)+(4-3)]
3
Oh, dude, if you bought 3 gross of pencils, you would have 432 pencils. Yeah, that's right, a gross is 144 pencils, so just multiply 144 by 3 and boom, you've got yourself a whole lot of pencils. Like, who even needs that many pencils, am I right?
432 = 3 x (12 x 12) = 3 x 144 = 3 gross
165