Nata spent $28 on 2 dvds. at this rate, how much would 5 cost? at what rate did she spend her money

we know that

Nata spent on DVDs

so

by proportion

Find the cost of DVDs

therefore

The answer Part a) is

The cost of DVDs is

Part b) Find the unit rate

we know that

Unit Rate is the ratio of two measurements in which the second term is

so

Find the cost of DVDs

therefore

the unit rate is

The answer Part b) is

Nata spent her money at the rate  

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."