rImITywR
In My Lane. In My Arrakis. In My Dune.
TLDW: Brown is orange. Its just a perception thing.
Some simplifying assumptions.
Let the distance from Earth to Mars be equal to 1, and assume it does not change. Let the direction from Earth to Mars be the positive direction.
Assume that the rockets travel at a constant velocity.
The displacement of the rockets can be represented with the lines
S_B(t) = (1/150)(t-30) = (1/150)t - (1/5)
S_A(t) = (-1/200)t + 1
Where t is time in days since rocket A took off. Notice rocket A has a negative slope (negative velocity) since it is moving from Mars to Earth. Rocket A has an initial position of 1, since it starts at Mars. Rocket B has a horizontal shift to the right of 30 days, representing it taking off later.
The rockets cross where these lines intersect. So
(1/150)t - (1/5) = (-1/200)t + 1
((1/150)+(1/200))t = 1 + (1/5)
(7/600)t = (6/5)
t = 720/7 ~= 103
So the rockets cross approximately 103 days after rocket A took off. The position at that time is
S_A(720/7) = (-1/200)(720/7) + 1
=(-18/35) + 1 = 17/35 ~= 0.49
So when they cross, they are about 49% of the way from Earth to Mars. Just closer to Earth than Mars.
When they cross each other, which one is the closet to the earth ?
This is why you read the while question before trying to answer it. When the cross, they are both the same distance from Earth.
Its not the 19th century anymore. Iodine deficiency is not a serious concern in most civilized countries. Most people can get enough iodine from their diets from dairy/eggs/fish/legumes.
You don’t need iodized salt, go ahead and use fancy salt. If you’re really concerned, take a multivitamin every now and then.
“[We] couldn’t tell the difference between France and [Quebec]”
Say that to a Quebecois. I dare you.
Also, removable batteries and waterproofing are not mutually exclusive. There have been flagships that were waterproof and had a removable battery, like the Galaxy S5. And there still are phones like that. Manufacturers have taken this away from us.
Also, also, every other industry has seemed to have figured it out. Go to the dollar store and you will find a flashlight that is waterproof and has easily replaceable AA batteries. Its not that complicated. Apple is one of the most successful companies on the planet, they can hire an engineer to come up with a decent solution. Apple et al. using waterproofing as an excuse to make the entire phone disposable when, not if, the battery dies is bullshit.