(4⁰ = 1 too small)
4¹ = 4
4² = 16
4³ = 64
4⁴ = 256
(4⁵ = 1,024 too big)
If each of them got 1/3 of the deck then they would each get 7 cards
It takes 4.3 seconds for the rocket to return to earth.
The equation is:

where -9.8m/sec² is the acceleration due to gravity, v₀ is the initial velocity, and h₀ is the initial height. We will go from the assumption that the rocket is launched from the ground, so h₀=0, and we are told that the initial velocity, v₀, is 42. This gives us:

We will use the quadratic formula to solve this. The quadratic formula is:

Plugging in our information we have:

x=0 is when the rocket is launched; x=4.3 is when the rocket lands.
Subtract 10 and collect terms to get the variable term by itself on the left.
... 4c = 24
Divide by the coefficient of the variable, 4.
... c = 6
The appropriate choice is the second one:
... 6
_____
You don't actually have to sove the equation to find the right answer. You just need to see which answer works.
-6: 5(-6) -(-6) +10 = -14 ≠ 34
6: 5(6) -(6) +10 = 34 . . . . . . . this answer works (you can stop here)
11: 5(11) -(11) +10 = 54 ≠ 34
-11: 5(-11) -(-11) +10 = -34 ≠ 34