6) Two boats set off from X at the same
time (below). Boat A sets off on a bearing of 325° and with a velocity of
14 km/h. Boat B sets off on a bearing of 2350 with a velocity of 18 km/h.
Calculate the distance between the boats after they have been travelling
for 2.5 hours. Give your answer to the nearest metre.
A
N
X Х
B​

Respuesta :

Answer:

The distance between the two boats after 2.5 hours is 57 m.

Step-by-step explanation:

The distance covered by each boat after 2.5 hours are:

speed = [tex]\frac{distance}{time}[/tex]

distance = speed x time

For boat A, speed = 14 km/h and time = 2.5 hrs.

So that,

distance = 14 x 2.5

              = 35 km

For boat B, speed = 18 km/h and time = 2.5 hrs.

So that,

distance = 18 x 2.5

              = 45 km

The distance between the two boats after travelling 2.5 hours can be determined by applying the cosine rule. Let the distance be represented by x, so that:

[tex]a^{2}[/tex] = [tex]b^{2}[/tex] + [tex]c^{2}[/tex] - 2bc Cos A

[tex]x^{2}[/tex] = [tex]45^{2}[/tex] + [tex]35^{2}[/tex] - 2(45 x 35) Cos [tex]90^{o}[/tex]

   = 2025 + 1225 - 3150 (0)

   = 3250

x = [tex]\sqrt{3250}[/tex]

  = 57.0088

x = 57.0 m

The distance between the two boats after 2.5 hours is 57 m.