Speed (S) = Distance (D) / time (t)
First stretch
45 = D / 2
D = 45*2
D = 90 mp
How is the same distance:
Second stretch
S = 90 / t
Average speed (AS):
AS = (S1+S2) / 2
60 = [45+(90/t)] / 2
120 = 45+90/t
120-45 = 90/t
75 = 90/t
t = 90/75
t = 1,2 h
________________________
And now:
S = 90 / t
S = 90 / 1,2
S = 75 mph
Your equation would be 2x - 12 + 3x - 15 = 23
Combine like terms and solve for x
Answer:
B. It is a composite number.
Step-by-step explanation:
143 can be divided by 11 and 13 making it a composite number.
Answer:
10 and 15
Step-by-step explanation:
Let 'x' and 'y' are the numbers we need to find.
x + y = 25 (two numbers whose sum is 25)
(1/x) + (1/y) = 1/6 (the sum of whose reciprocals is 1/6)
The solutions of the this system of equations are the numbers we need to find.
x = 25 - y
1/(25 - y) + 1/y = 1/6 multiply both sides by 6(25-y)y
6y + 6(25-y) = (25-y)y
6y + 150 - 6y = 25y - (y^2)
y^2 - 25y + 150 = 0 quadratic equation has 2 solutions
y1 = 15
y2 = 10
Thus we have
:
First solution: for y = 15, x = 25 - 15 = 10
Second solution: for y = 10, x = 25 - 10 = 15
The first and the second solution are in fact the same one solution we are looking for: the two numbers are 10 and 15 (since the combination 10 and 15 is the same as 15 and 10).
Answer:
Step-by-step explanation:
