Answer:
2.5 meters per second
Step-by-step explanation:
Given,
The speed of Charlotte = 9 km/h
That is, the distance covered in 1 hour = 9 km,
∵ 1 km = 1000 m
So, the distance covered in 1 hour = 9000 m,
∵ 1 hour = 60 minutes and 1 minute = 60 seconds,
⇒ 1 hours = 3600 seconds,
∴ The distance covered in 3600 seconds = 9000 m,
⇒ Distance covered in 1 second = = 2.5 m,
Hence, his/her speed = 2.5 meters per second
Answer:
Step-by-step explanation:
Represent the volume of the box with V and the dimensions with l, b and h.
The volume (V) is:
Make h the subject of the formula
The surface area (S) of the aquarium is:
Where lb represents the area of the base (i.e. slate):
The cost (C) of the surface area is:
Substitute for h in the above equation
Differentiate with respect to l and with respect to b
To solve for b and l, we equate both equations and set l to b (to minimize the cost)
By comparison:
becomes
Cross Multiply
Solve for l
Recall that:
Also recall that:
Apply law of indices
The dimension that minimizes the cost of material of the aquarium is: