A train travels 524 miles in 4, 1/2 hours. Which expression gives the train's speed in miles per hour?
1 answer:
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Answer:
The answer is 36
Step-by-step explanation:
Let the number be <em>x</em>
x/40 is her mark
she got 90% mark correct
x/40 x 100 = 90
by cancellation we get 9 x 4 = 36
HOPE THIS HELPS
Answer:
Positive discriminant = 2 real solution
x= -5,-40
Step-by-step explanation:
The discriminant is used to see how many solutions an equation has. If it is negative, the equation has no real solutions, if =0 the equation has 1, and if it is positive, the equation has two real solutions.
The discriminant is the part of the quadratic formula inside the square root:
Every quadratic formula has the structure:
So first, in order to meet this structure we need to add 200 to both sides so the equation is equal to 0. This gives us:
Our a=1, b=45 and c=200
Now we can substitute these values into the discriminant:
Solve:
The discriminant is a positive number which means this equation will have 2 real solution. Now we just need to plug in our values into the quadratic formula to solve this equation. Quadratic formula:
(Same discriminant value)
Now to find the two solutions, we use both signs in the equation. Solution 1:
Our first solution is -5, now for the second:
The two solution to this equation are -5 and -40.
Hope this helped!