Ying Zyiyu covers the first 300 miles of a trip traveling at 60 mph. and the last hundred miles traveling at 40 mph. What was his average speed for the entire trip?

53.33 mph

Step-by-step explanation:

Speed is the rate of change of distance with time. Mathematically,

speed = distance/time

and is measured in miles per hour or meter per second.

To get the average speed over the entire trip, we must get the total time  spent on trip and the total distance, then apply the speed formula

Time for the first 300 miles

= 300/60

= 5 hours

Time spent on the last 100

= 100/40

= 2.5 hours

Total time of the trip = 5 + 2.5

= 7.5 hours

Total distance covered

= 300 miles + 100 miles

= 400 miles

Average speed on the trip

= 400/7.5

= 53.33 miles per hour

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3

the answer is a beach is the best place to be