Marcus can drive his boat 24 miles down the river in 2 hours but takes 3 hours to return upstream. find the rate of the boat in still water and the rate of the current.

speed of boat as

river speed is given as

Explanation:

When boat is moving down stream then in that case net resultant speed of the boat is given as

since the boat and river is in same direction so we will have

Now when boat moves upstream then in that case the net speed of the boat is opposite to the speed of the river

so here we have

as we know when boat is in downstream then in that case it covers 24 miles in 2 hours

also when it moves in upstream then it covers same distance in 3 hours of time

so we have speed of boat as

river speed is given as

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia