Question

Difficulty: MediumExponents, Roots, and Scientific Notation

A rectangular field has a length of 1.5×1041.5 \times 10^4 meters and a width of 4.0×1034.0 \times 10^3 meters. If a tractor can mow 6.0×1056.0 \times 10^5 square meters per hour, how many hours will it take the tractor to mow the entire field?

Answer: 100 hours

Answer

It will take 100 hours for the tractor to mow the entire field.
The total area of the field is the product of its length and width: (1.5×104)×(4.0×103)=6.0×107(1.5 \times 10^4) \times (4.0 \times 10^3) = 6.0 \times 10^7 square meters. Dividing this area by the tractor's mowing rate of 6.0×1056.0 \times 10^5 square meters per hour gives 6.0×1076.0×105=1.0×102=100\frac{6.0 \times 10^7}{6.0 \times 10^5} = 1.0 \times 10^2 = 100 hours.

Step-by-Step Solution

1
Calculate the area of the rectangular field.
Area = 6.0×1076.0 \times 10^7 square meters
The area of a rectangle is found by multiplying its length by its width: (1.5×104 m)×(4.0×103 m)=6.0×107 m2(1.5 \times 10^4 \text{ m}) \times (4.0 \times 10^3 \text{ m}) = 6.0 \times 10^7 \text{ m}^2.
2
Calculate the time required to mow the field.
Time = 100100 hours
Divide the total area by the tractor's mowing rate: 6.0×107 m26.0×105 m2/hour=1.0×102=100\frac{6.0 \times 10^7 \text{ m}^2}{6.0 \times 10^5 \text{ m}^2/\text{hour}} = 1.0 \times 10^2 = 100 hours.

Key Concept

Multiplication and division of numbers in scientific notation
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