express in roster form: B={xlxE N and 6

Question

express in roster form: B={xlxE N and 6<x<10}

myininaya · Answer

Just list all the natural numbers in the interval (6,10)

anonymous · Answer

B={7,8,9}

myininaya · Answer

Yep, that is right.

anonymous · Answer

thanks

myininaya · Answer

np

anonymous · Answer

what is np?

anonymous · Answer

myininaya', what if the set Q of all prime numbers less than 10? can we consider the negative numbers?

myininaya · Answer

I think it depends on the definition of prime numbers your teacher chose.
I choose the definition that they are natural numbers greater than 1 and are only divisible by 1 and itself.
For example: 13 since 13 and 1 are it's only factors

unklerhaukus · Answer

$$\{n\in \mathcal N |(1<n<10)∧(\forall x,y\in  \mathcal N)[(xy=n)⇒(x=1∨y=1)]\}$$

myininaya · Answer

So do you think you can now list the prime numbers between 1 and 10 (not including 10 since it doesn't say equal to)?

anonymous · Answer

yap

anonymous · Answer

A math teacher is preparing an exam each of his Algebra class. Math-alino and Math-matalino, 
    covering topics A (circles) and B (inequalities). He wants to design the exams so that both classes 
   will have the same number of questions on A and also on B. Each question on A is worth 15    
    points  in section Math-alino and 20 points in section Math-matalino while each question on B is 
    worth 10 points in  section  Math-alino and 5 points in section Math-matalino. If the total number 
   of points in both exams is 100, how many questions should he ask on each  topic?

anonymous · Answer

help me please UnkleRhaukus thanks in advance

unklerhaukus · Answer

too confusing