John has some coins, that are of two different denominations worth $2.55. The equations model the coins that John has. x + y = 15 and .10x + .25y = 2.55.a. How many coins does John have?b. Which expression represents the total cost of the dimes?c. Which expression represents the total cost of the quarters?d. How do you know your answers to part b and c are correct?e. In your own words, what does the equation x + y = 15 represent?

5y

step-by-step explanation:

- "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."