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Algebra Difficulty 3.8 AMC 10/12 Find the answer North Macedonia

During three hours a driver with a car has driven 180 km180\,km. During the first hour he has driven 0.3750.375 from the whole distance and during the second hour he has driven 0.90.9 from the distance that he had driven during the first hour. What distance has the driver driven during the third hour?

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

Solution

The third hour the driver has driven 180−0.375⋅180−0.9⋅0.375⋅180=51.75 km=51 km 75m180 - 0.375 \cdot 180 - 0.9 \cdot 0.375 \cdot 180 = 51.75\,km = 51\,km\ 75m.

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