Answer:
See Explanation
Explanation:
Given
![D = s.t](https://img.qammunity.org/2022/formulas/mathematics/high-school/uo43z01uyhxt0u47xlzj6ugsxjtag2i7xa.png)
Required
Which represents 400km
This question requires options. Since none were given, I will answer on a general term.
Situation 1:
s = 20km/h and t = 20h
![D = s.t](https://img.qammunity.org/2022/formulas/mathematics/high-school/uo43z01uyhxt0u47xlzj6ugsxjtag2i7xa.png)
![D = 20km/h * 20h](https://img.qammunity.org/2022/formulas/mathematics/high-school/n223evwjrd2uwiz9ttmul99fjg5ipn1fx8.png)
![D = 400km](https://img.qammunity.org/2022/formulas/mathematics/high-school/dhnfrl3qo1nzlva5v7uc2kjysom4717122.png)
Situation 2:
s = 10km/h and t = 40h
![D = s.t](https://img.qammunity.org/2022/formulas/mathematics/high-school/uo43z01uyhxt0u47xlzj6ugsxjtag2i7xa.png)
![D = 10km/h * 40h](https://img.qammunity.org/2022/formulas/mathematics/high-school/657x4js0fre376qkg0ty44afnywv46f2to.png)
![D = 400km](https://img.qammunity.org/2022/formulas/mathematics/high-school/dhnfrl3qo1nzlva5v7uc2kjysom4717122.png)
Situation 3:
s = 40km/h and t = 10h
![D = s.t](https://img.qammunity.org/2022/formulas/mathematics/high-school/uo43z01uyhxt0u47xlzj6ugsxjtag2i7xa.png)
![D = 40km/h * 10h](https://img.qammunity.org/2022/formulas/mathematics/high-school/b3imaa2mvzoriqqn7vo0stf7ryzavzoyxx.png)
![D = 400km](https://img.qammunity.org/2022/formulas/mathematics/high-school/dhnfrl3qo1nzlva5v7uc2kjysom4717122.png)
So, all you literally have to do is multiply the values of s and t. If the product gives 400, then; that situation is D = 400