The complete question in the attached figure
we know that
the root mean square speed, is the square root of the average (mean) of all of the square of the speeds of individual particles in a gas.
step 1
find the square of the speeds of individual particles
2.8²----> 7.84
3.2²---->10.24
5.8²----> 33.64
7.3²----> 53.29
7.4²---> 54.76
average=[7.84+10.24+33.64+53.29+54.76]/5-----> 159.77/5----> 31.954
step 2
find the square root of the average
√31.954=5.65
therefore
the answer isthe option b) 5.7 m/s
We have to write an equation that uses this info so we can find the cost to ship that package. However, the package weight is given to us in grams and we need it in ounces. So first thing we are going to do is convert that 224 g to ounces. Use the fact that 1 g = .035274 ounces to convert. 
. Do the multiplication and cancel out the label of grams and we have 7.901376 ounces. Ok. We know that it costs .57 to mail the package for the first ounce. We have almost 8 ounces. So no matter what, we are paying .57. For each additional ounce we are paying .32. The number of .32's we have to spend depends upon how much the package goes over the first ounce. For the first ounce we pay .57, then for the remaining 6.901376 ounces we pay .32 per ounce. Our equation looks like this: C(x) = .32(6.901376) + .57 and we need to solve for the cost, C(x). Doing the multiplication we find that it would cost $2.78 to ship that package.
First, plot the points in a graph to see the general trend. The independent variable is time. I used MS Excel to plot the points in a graph, as shown in the attached picture.
1. The relationship is linear as shown in the general trend.
2. The relationship presents that as time increases, the number of apartments cleaned also increases. The two variables are directly proportional.
3. The rate of change represents the slope of the line. Choose any two points and find the slope.
m = (6-3)/(2-1) = 3 apartments cleaned/hour
