Answer:
Susie reaches the store first being ahead by 0.06 hours.
Step-by-step explanation:
20 miles going 45 miles/hour.
20 miles / (45 miles / hour) = 20 miles hours / 45 miles =
= 20 hours / 45 = 4/9 hours = 0.44 hours
25 miles going 50 miles/hour.
25 miles / (50 miles / hour) = 25 miles hours / 50 miles =
= 25 hours / 50 = 1/2 hours = 0.5 hours
So Susie needs less time (= arrives first).
the difference is 0.5 - 0.44 = 0.50-0.44 = 0.06 hours
as additional practice :
0.06 hours is 60 × 0.06 minutes.
60 × 0.06 = 60 × 6 / 100 = 360 / 100 = 3.6 minutes.
Answer:
f(n) = -n^2 -3n +5
Step-by-step explanation:
Suppose the formula is ...
f(n) = an^2 +bn +c
Then we have ...
f(1) = 1 = a(1^2) +b(1) +c
f(2) = -5 = a(2^2) +b(2) +c
f(3) = -13 = a(3^2) +b(3) +c
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Here's a way to solve these equations.
Subtract the first equation from the second:
-6 = 3a +b . . . . . 4th equation
Subtract the second equation from the third:
-8 = 5a +b . . . . . 5th equation
Subtract the fourth equation from the fifth:
-2 = 2a
a = -1
Then substituting into the 4th equation to find b, we have ...
-6 = 3(-1) +b
-3 = b
and ...
1 = -1 +(-3) +c . . . . . substituting "a" and "b" into the first equation
5 = c
The formula is ...
f(n) = -n^2 -3n +5
Jim is ranked third best in his class of 50 students.
Answer: B. (-2, 3)
Step-by-step explanation: The two lines have the same solution where both lines intersect. So, if you look at the point on the graph where the two lines intersect, and count the tick marks on the number lines, the point is clearly located at (-2, 3).
This relationship again shows that since w and y are perpendicular to each other that the smaller angles will add up to give 90 degrees.
3x + 3 + 15 = 90
3x + 18 = 90
3x = 90 - 18
3x = 72
X =72/3
X = 36 degrees
