8/4 = 55/x
8x = 55(4)
8x = 220
x = 27.5
answer
<span>b. 27.5</span>
Let p and w represent the speed of the plane and the speed of the wind, respectively.
.. speed = distance/time
.. p +w = 720/3 = 240
.. p -w = 720/4 = 180
Add the two equations to eliminate w.
.. 2p = 420
.. p = 210
.. w = p -180 = 30
The speed of the wind is 30 mph.
The speed of the plane in still air is 210 mph.
After understanding the problem, formulate equations to determine the unknown. Let x be the price of one book. Equating Alana&Petra's expense with Angus' would be
5x + 4x +5 = 19x - 10
The 5 in the left side is needed because Angus' expense is $5 more. Also, the 10 on the right side represents the $10 discount. Solving the equation,
19x = 9x = 5+10
10x = 15
x = $1.5
Therefore, the book costs $1.5.
Answer:
-3b - 21
Step-by-step explanation:
You have distribute the -3 to both b and 7. So, you would have to multiply the -3 to both b and 7.
