Answer:
The speed of the current is 3 miles per hour
Step-by-step explanation:
The equations for rate (r), distance (d), and time (t) are ⇒ d = rt, r = d/t, = t = d/r
Let x = speed in still water
Let c = speed of the current
The main difference with these problems is rate needs to be expressed using two variables because moving upstream the current is against you and downstream it moves with you.
Distance Rate Time
Upstream x − c
Downstream x + c
The distance column with the numbers from the problem and the value for speed in still water for x.
Distance Rate Time
Upstream 4 5 − c
Downstream 16 5 + c
The column for time using the other two columns knowing that rate, distance ⇒ time = Distance Rate Time
Upstream 4 5 − c
5 − c
4
Downstream 16 5 + c
5 + c
16
“It takes as long …” from the problem means that the two times are equal to each other. So, the equation can be written as:
4/5− c = 16/5 + c ⇒ Solve by cross-multiplying ⇒ 5(4 + c) = 16 5( − c) ⇒ c = 3
Answer:
B
Step-by-step explanation:
Answer:
66.9 degrees
Step-by-step explanation:
The Law of Sines states that a/sinA = c/sinC. Plugging in the values for c, a, and M < A, we get:
71/sin40 = 102/sinC
Cross multiplying, we get:
102(sin40deg) = 71(sinC)
Now, we simplify the left side and get:
65.56 = 71(sinC)
Next, we divide 65.56 by 71 to get:
0.92 = sinC
Taking the inverse sign we get:
C = 66.9 degrees
Remember that cents has a decimal when put in an equation.
250(x + 11) + 250x = 4250
250x + 2750 + 250x = 4250
500x + 2750 = 4250
500x = 1500
x = 3 cents (pencils)
x+11 = 14 cents (pens)
Answer:
33 batteries
Step-by-step explanation:
14 batteries per 3-night trip
(14/3): batteries used per night
(14/3)* 7(nights) = (98/3) ≈ 33 (you have to round up)
