Answer:
B. Lin can type 4 more words per minute than Hoi.
Explanation:
We have been given that Lin can type 192 words in 6 minutes. Hoi can type 112 words in 4 minutes.
First of all, we will find per minute typing speed of Lin and Hoi as:
![\text{Typing speed of Lin}=\frac{192\text{ words}}{\text{6 minutes}}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/93ug6i8t5gwgwkp6cjzys540vj3prfr8ba.png)
![\text{Typing speed of Lin}=32\frac{\text{ words}}{\text{ minutes}}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/bvtr616dbwopikc2io0ljv7iwkvurzj59p.png)
Therefore, Lin's typing speed is 32 words per minute.
![\text{Typing speed of Hoi}=\frac{112\text{ words}}{\text{4 minutes}}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/gjwd9ldzexq24fvnb551s90cinljka5uge.png)
![\text{Typing speed of Hoi}=28\frac{\text{ words}}{\text{ minutes}}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xspzvbr0c3wgoxd3qmd0sh8he8s214p54s.png)
Therefore, Hoi's typing speed is 28 words per minute.
We can see that Lin's typing speed is 4 more (32-28) words per minute more than Hoi, therefore, option B is the correct choice.