Answer:
60km
Step-by-step explanation:
There are two ways to look at this
1. Finding the unit rate
We can find how many km he travels in 1 hour by diving both the hours and km by 2. 1 hour = 10km so 6 hours is 60km since we multiply by 6.
2. Multiply by 3
We can multiply both the km and hours by 3, since 2x3=6 hours
20km * 3 hours = 60km
Number 1 is x=2.2 and number 2 is x=4.3
Answer: 24 grams of element would remain.
Step-by-step explanation:
Exponential function for decay:
....(i) , where A = initial value , b = decay factor, x = time , n= time per period
As per given,
A = 569 grams , 
n= 5 years, t = 23 years
Put all values in (i) , we get

Hence, after 23 years , 24 grams of element would remain.
We are given with the number of jumps per student. To get the mean, we simply have to add all of them and divide by the number of students
mean number of jumps = <span>203 + 245 + 237 + 233 + 90 + 100 + 100 + 277 + 265 + 264 + 265 + 285 + 288 + 291 + 291 + 290 + 300 + 224 + 200 + 257 + 290 + 279 + 266 + 288) / 24
To get th median, arrange the data from lowest to highest and determine the middle value.</span>