A visitor is staying in a tent that is 7 kilometers east of the closest point on a shoreline to an island. The island is 3 kilometers due south of the shoreline. The visitor plans to travel from the tent to the island by running and swimming. If the visitor runs at a rate of 6 kmph and swims at a rate of 5 kmph, how far should the visitor run to minimize the time it takes to reach the island?

this is answer of 144 cubic meters

any options?

step-by-step explanation:

place r′ so that qr′ is parallel to the tangent.

now we get that ∠r′py=∠pr′q, where y is on the tangent, on the opposite side of p from x.

also, because of the symmetry, ∠r′py=∠qpx.

finally, note that no matter where we place r, as long as it's on the correct arc, we have ∠prq=∠pr′q.

stringing all these equalities together, we end up with ∠prq=∠qpx.

this picture will show how its going to look like.

hope this by jack monhen