Answer:
5 hours
Step-by-step explanation:
Step one:'
given data
Angelo charges a one time fee of $50 plus $15 per hour
let the total charge be y
and the number of hours be x
y= 50+15x----------------1
Deborah charges a one time fee of $25 plus $20 per hour
y= 25+20x----------------2
equate 1 and 2 to find x
50+15x=25+20x
collect like terms
50-25= 20x-15x
25= 5x
divide both sides by 5
x= 25/5
x= 5 hours
11k+6
You add same variables the add/subtract normal #s
Answer:
B
Step-by-step explanation:
the mean is calculated as
mean = 
this year's mean = 
= 
= 4.1
last year's mean = 
= 
= 3.1
difference = 4.1 - 3.1 = 1
Answer:
12.5 ft/s
Explanation:
Height of person = 6 ft
height of lamp post = 10 ft
According to the question,
dx / dt = 5 ft/s
Let the rate of tip of the shadow moves away is dy/dt.
According to the diagram
10 / y = 6 / (y - x)
10 y - 10 x = 6 y
y = 2.5 x
Differentiate both sides with respect to t.
dy / dt = 2.5 dx / dt
dy / dt = 2.5 (5) = 12.5 ft /s
