Marked a certain solution of salt water is 10% salt and weighs 50 pounds. more salt must be added to produce a solution that is 25% salt. if x represents the pounds of salt to be added, which of the following expressions represents the number of pounds of salt in the 25% solution? a)0.25(x+50) b) 0.25x c) 1.25(x+50)

4a. is 3 miles every hour

4b. is 1/3 of an hour per mile

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."