Step-by-step explanation:
2(10)+2(x+4)
20 + 2x + 8
20 +8 +2x
28+2x
Answer:
Actual correct answer (I checked because the first answer was wrong)
Step-by-step explanation:
x product of powers
quotient of powers
power of a power
x power of a product
negative exponent
x zero exponent
I got this right the second time.
The Earth is a watery place. But just how much water exists on, in, and above our planet? About 71 percent of the Earth's surface is water-covered, and the oceans<span> hold about 96.5 percent of all Earth's water. Water also exists in the air as </span>water vapor<span>, in </span>rivers<span> and </span>lakes<span>, in icecaps and </span>glaciers<span>, in the ground as soil moisture and in </span>aquifers<span>, and even in you and your dog.</span>
<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