Answer:
A
Step-by-step explanation:
Equation
2x + 3x + 8 + 7x - 2 = 90
Solution
Combine like terms on the left
12x + 6 = 90 Subtract 6 on both sides
12x = 90 - 6
12x = 84 Divide by 12
x = 84/12
x = 7
F - for simplification - we assume the orbits are circular (which they approximately are), we have a centrifugal force of <span><span>m<span><span>v2</span>R</span></span><span>m<span><span>v2</span>R</span></span></span><span>, where </span>m<span> is the mass of the planet, </span>v<span> its speed, and </span>R<span> the distance from the (center of the) sun. This force must be equal to the centripetal force, which comes from the sun's attraction, and it is </span><span><span>mG<span>M<span>R2</span></span></span><span>mG<span>M<span>R2</span></span></span></span><span>. Here, </span>M<span> is the mass of the sun, and </span>G<span> is a constant. We don't care about the actual numbers, so we write </span>C<span> be the product </span>MG<span> and observe that it is a constant independent of the orbit. These forces have to cancel out, so we have </span><span><span><span>v2</span>R=C<span>R<span>−2</span></span></span><span><span>v2</span>R=C<span>R<span>−2</span></span></span></span><span>, or </span><span><span><span>v2</span>=C<span>R<span>−3</span></span></span><span><span>v2</span>=C<span>R<span>−3</span></span></span></span><span>, so we have that the speed is proportional to </span><span><span>R<span><span>−3</span>2</span></span><span>R<span><span>−3</span>2</span></span></span><span>. Which means that if you decrease the distance to the sun, the speed goes up.</span>
62,000x42= 2,604,000 gallons a day
Times that by 7 to get one week
Then by 7 again for 7weeks then 4 to get 28 weeks :)
7 weeks= 127,596,000
28 weeks= 510,384,000
