Answer:
your answer is 121
Step-by-step explanation:
2x² - 3xy
2(1)² - 3(1)(2)
2(1) - 3(2)
2 - 6
-4
Answer:
56
Step-by-step explanation:
a dime =10 cent
divide 5.6 by 0.1=56
<h3>Rate of the boat in still water is 70 km/hr and rate of the current is 15 km/hr</h3><h3><u>Solution:</u></h3>
Given that,
A motorboat travels 165 kilometers in 3 hours going upstream and 510 kilometers in 6 hours going downstream
Therefore,
Upstream distance = 165 km
Upstream time = 3 hours
<h3><u>Find upstream speed:</u></h3>

Thus upstream speed is 55 km per hour
Downstream distance = 510 km
Downstream time = 6 hours
<h3><u>Find downstream speed:</u></h3>

Thus downstream speed is 85 km per hour
<em><u>If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then</u></em>
Speed downstream = u + v km/hr
Speed upstream = u - v km/hr
Therefore,
u + v = 85 ----- eqn 1
u - v = 55 ----- eqn 2
Solve both
Add them
u + v + u - v = 85 + 55
2u = 140
u = 70
<em><u>Substitute u = 70 in eqn 1</u></em>
70 + v = 85
v = 85 - 70
v = 15
Thus rate of the boat in still water is 70 km/hr and rate of the current is 15 km/hr
Answer:
0.4 sec
Step-by-step explanation:
Remember that
1 mile=5,280 feet
1 foot=12 inches
1 hour=3,600 seconds
Let
s -----> the speed in ft/sec
d ----> the distance in ft
t -----> the time in sec
s=d/t
Solve for t
t=d/s
step 1
Convert miles/hour to ft/sec
105 mi/h=105(5,280/3,600)=154 ft/sec
Convert 60 ft 6 in to ft
60 ft 6 in=60+(6/12)=60.5 ft
step 2
Find the time
t=d/s
we have
s=154 ft/sec
d=60.5 ft
substitute
t=60.5/154
t=0.39 sec
Round to the nearest tenth
t=0.4 sec