Harry drove for 5 hours on the freeway, then decreased his speed by 20 miles per hour and drove for 3 more hours on a country road. If his trip total was 396 miles, then what was his speed on the freeway?
speed*5+(speed+20)3=396
solve for speed
57 mi/h
To find out Harry's speed on the freeway, we can use the formula: Distance = Speed x Time.
Let's start by calculating the distance Harry traveled on the freeway. He drove for 5 hours, so the distance he covered on the freeway can be calculated as 5 x Speed. Let's call this distance D1.
Next, let's calculate the distance Harry traveled on the country road. He drove for 3 hours, and his speed decreased by 20 mph. So, his speed on the country road would be (Speed - 20) mph. This distance can be calculated as 3 x (Speed - 20). Let's call this distance D2.
Now, according to the given information, the total distance Harry traveled is 396 miles. So, D1 + D2 = 396.
Substituting the calculated expressions for D1 and D2 into the equation, we get:
5 x Speed + 3 x (Speed - 20) = 396.
Now, we can simplify the equation:
5S + 3S - 60 = 396,
8S = 456,
S = 456 / 8,
S = 57.
Therefore, Harry's speed on the freeway was 57 miles per hour.