The word about tells us that we are being asked to estimate.
About 3 hours
Practice makes perfect
We have been asked to estimate the number of hours it will take the drill to reach a depth of 300 meters given that it drills at a rate of 67 m/h. We are also told that the drill starts at 75 meters below the surface. To find the distance that the drill still needs to go, we need to subtract 75 from 300.
300-75=225 meters
With the given rate, in one hour the drill gets a distance of 67 meters. This is not deep enough. Let's try 5 hours.
67* 5 = 335 meters
This value is a bit more than we need. Let's try 3 hours this time.
67*3=201 meters
This is very close to 225. Therefore, the total depth after 3 hours will be almost 300 meters, so our answer is about 3 hours.
Equation
Let's build the equation that would model this scenario.
Phrase
Expression
Distance from drill starting point to the total depth
225
Drilling rate is 67 meters per hour h
67h
Time it takes for the drill to reach the bottom
67h=225
The equation to model this scenario is 67h=225.
Needed Integers
To write this equation we needed to consider the integer values of the drilling rate, 67, the total depth, 300, and the starting point of the drill, 75.
