Question

Scientists on an oceanographic research vessel board a miniature submarine when it is at an elevation of 2 meters above the ocean's surface.

The ocean floor directly beneath the boat is at a depth of 180 meters.The submarine descends at a constant rate of 0.4 meters per second. How long, in seconds, could a scientist spend descending after boarding the submarine?
A. x < 455
B. x < 450
C. x > 445
D. x > 450

Answer 1

x < 455

Explanation:

Given : Submarine is at an elevation of 2 meters above the ocean's surface.

The ocean floor directly beneath the boat is at a depth of 180 meters

The submarine descends at a constant rate of 0.4 meters per second.

To Find : How long, in seconds, could a scientist spend descending after boarding the submarine?

Solution :

Submarine is at an elevation of 2 meters above the ocean's surface

The ocean floor directly beneath the boat is at a depth of 180 meters

So, distance traveled by scientist descending after boarding the submarine = 180 m + 2m = 182 m

The submarine descends at a constant rate of 0.4 meters per second.

So, a scientist spend seconds in descending after boarding the submarine =
`(182)/(0.4)=455`

So, a scientist spend 455 seconds or less than that descending after boarding the submarine

So, Option A is true

So, x < 455

Answer 2

Answer: Option 'A' is correct.

Explanation:

Since we have given that

The ocean floor directly beneath the boat is at a depth of = 180 meters

Submarine is at an elevation when it is above the ocean's surface = 2 meters

Total distance submarine needs to descends at a constant rate = 180+2=182 m

Rate of submarine descends = 0.4 meters per second.

Time taken by a scientist spend descending after boarding the submarine is given by

`Time=(Distance)/(Speed)\\\\Time=(182)/(0.4)\\\\Time=455\ seconds`

so, it must be less than 455 seconds.

therefore, it becomes x<455.

Hence, Option 'A' is correct.