Question

A submarine begins 300 feet below sea level. It makes four moves of 30 feet each

toward the surface. How many more feet does the submarine need to move to reach
the surface?

Answer 1

180 feet

Explanation:

Starting number is 300. Four moves of 30 feet is 120 feet.

30x4 = 120

300-120 = 180

Answer 2

180 feet.

Explanation:

Remark

You need some formal way of expressing what is happening. You start at 300 feet below sea level, and make make 4 moves of 30 feet each. Where are you and how much further do you have to go to reach the surface?

Equation

Distance to go = distance in feet below sea level - number of moves * feet / move.

Givens.

original distance below sea level = 300 feet.

number of moves = 4

distance towards the surface for each move = 30 feet.

Distance to go. = ?

Solution

Distance to go = 300 - 4*30

Distance to go = 300 - 120

Distance to go = 180 feet