stuck on inequality question

[eric beans]

Which two of these statements are equivalent?
1. Steve is not younger than Mike.
2. Mike is younger than Steve.
3. Steve is not older than Mike.
4. Mike is at least as old as Steve.

i don't understand why 3 and 4 are the same. can someone explain this? how would you diagram this to solve?

 

[JOwen56]

Can you assign a variable to each name, and then write a pair of inequalities? That may help you see that they are the same.

 

[HallsofIvy]

Do you understand the difference between "not older than" and "younger than"? When could one be true and the other false?

 

[lex]

 

[JeffM]

Which two of these statements are equivalent?
1. Steve is not younger than Mike.
2. Mike is younger than Steve.
3. Steve is not older than Mike.
4. Mike is at least as old as Steve.

i don't understand why 3 and 4 are the same. can someone explain this? how would you diagram this to solve?

When you do not understand a general statement, try a specific example.

Mike is 15. If Steve is not older, then Steve could be any age under 16. In which case, Mike is not younger. But ‘not younger’ means the same thing “at least as old.”

Now you could pick any age. You could have said Mike was 8. Would that make any difference to the analysis? You test a general statement with specific instances until you are satisfied.

 

[lookagain]

eric beans, to pick out a relatively troublesome statement, number four means
"Mike's age, at a minimum, is equal to Steve's age." Or, put another way, "Mike's
age is greater than or equal to Steve's age."