Aculture starts with 4000 bacteria after 5 hours it has 4800 how many bacteria after 15 hours

6400

Step-by-step explanation:

so every 5 hours it gains 800 bacteria so 4800+800=5600 (hour 10)

and 5600+800=6400 (hour 15)

28000

Step-by-step explanation:it gains 8000 bacteria every 5 hours and there are 3 fives in fifteen times 8000*3=24000 then add 4000

- "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."

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.