Evaluate. 2 • {390 – [5 • (10 – 4 ÷ 2)] + 15} • 2
1 answer:
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Answer:
First part: 2 miles.
Second part: 45 minutes
Third part: 8 mph.
Step-by-step explanation:
We can divide this question into 3 parts.
Begin by solving for the distance traveled after 15 minutes by creating a ratio:
Cross multiply:
20 · 15 = 150 · x
300 = 150x
300/150 = 150x/150
x = 2 miles.
2nd part: How long it took her to ride 6 miles.
Set up another ratio similar to the one used before:
Cross multiply:
20 · x = 6 · 150
20x = 900
20x/20 = 900/20
x = 45 minutes.
3rd part:
For this part, we will need to convert from minutes to hours.
Therefore, her speed is 8 mph.
To solve this one-step equation you:
1. Substract 9 in both sides of the equation:
In this step is the mistake as Sara gets as result -4x=29 and the corret result of substract 9 in both sides of the equation is 5x=20.2. Divide both sides of the equation into 5:
Then, the answer that Sara should found for the equation is x=4