Answer: The equations are
6x - 6y = 9
4x + 4y = 9
Step-by-step explanation:
Let x represent the speed of the row boat in still water.
Let y represent the speed of the current.
Dana can travel 9 miles in her rowboat in 6 hours against the current. This means that the total speed at which she travelled is
(x - y) miles per hour.
Distance = speed × time
Distance travelled against the current is expressed as
9 = 6(x - y)
6x - 6y = 9
With the current, it takes 4 hours to row the same distance. This means that the total speed at which she travelled is
(x + y) miles per hour.
Distance travelled with the current is expressed as
9 = 4(x + y)
4x + 4y = 9
Answer: 8.3
Step-by-step explanation:
To find the variance, you want to find the mean of the data.

Now that we have the mean, we find the difference between each data point and the mean.
3-5=-2
3-5=-2
8-5=3
1-5=-4
9-5=4
6-5=1
With the difference, you square each and find the average.
(-2)²=4
(-2)²=4
3²=9
(-4)²=16
4²=16
1²=1

The variance is 8.3.
ANSWER:
We have to find new side-lengths of PQR triangle.
Original sides are.

After multiplying by 2.5 we get

These are the new sides of the P'Q'R' triangle.