We can convert 20km to 20,000m. Then, we can subtract 800m (walking distance) from 20,000m which would result in 19,200m. Then we can put 19,200m and 20,000m as a fraction (19200/20000). Before we can multiply it by 100 to make it in the percentage form, we can get rid of 2 zeroes for both number making it 192/200 and then further simplifying it to 24/25 by dividing both numbers by 8. Finally to get the percentage we can multiply 24 and 100 (2400) and then divide the result (2400) by 25. The final answer is 2400/25=96 meaning he cycled 96% of the journey and walked 4% of the journey (100-96=4).
Step-by-step explanation:
Distance = rate × time
If B is the rate of the boat, and C is the rate of the current, then we can write two equations:
18 = (B + C) × 3
18 = (B − C) × 9
Simplifying the equations:
6 = B + C
2 = B − C
Add the equations together to eliminate C:
8 = 2B
B = 4
Plug into either equation to find C:
C = 2
The boat's rate is 4 mph, and the current's rate is 2 mph.