1. A store sells mints for 50 cents or $4.8 a pack (12). Q: How much is the unit price of a mint higher than that of a packet?

[50-(480/ 12)]/(480/ 12)=25%

2. It is known that m is a positive integer and 3+ 16/m is an integer less than 19. Which of the following statements must be true? ( )

A: M = 19b: M is an even number C: M = 16d: M is a prime number E: M is a multiple of 4.

Choose B.

A: 3+ 16/ 19 is not an integer. A is wrong.

B:∫3+ 16/m is an integer less than 19.

∴ 16/m is an integer less than 16.

∴m is a factor of 16.

The prime factor of 16 is 2.

∴m is a multiple of 2, that is, m is an even number.

C: 3+16/2 =11is also an integer less than 19, m is not necessarily16, and c is not necessarily correct.

D: 3+ 16/4 = 7 is also an integer less than 19, m=4 is a composite number, and d is wrong.

E: 3+16/2 =11is also an integer less than 19, and m=2 is not a multiple of 4. E is wrong.

Finally: come on, landlord!