Anewly discovered planet is found to have a density if 2/3pe and a radius of 2re, where pe and red are the density and radius of earth, respectively.

Missing question in the text of the exercise. Found on internet:
"What is the acceleration due to gravity on the surface of the planet?"

Solution:
The gravitational acceleration at Earth's surface is given by:
 
where
G is the gravitational constant
M is the Earth's mass
r is the Earth's radius

The Earth's mass can be rewritten also as the product between the Earth's density, , and its volume (the volume of a sphere of radius r):
 

Now let's call M' the mass of the new planet, r' its radius and d' its density. The acceleration due to gravity on the surface of the new planet is
(1)
so we need to find M' and r'.

The problem says the radius of the new planet is twice the Earth's radius: 
(2)
and that its density is 2/3 of Earth's density:

so the mass M' of the new planet is, with respect to the Earth's mass:
(3)

And if we substitute (2) and (3) into (1), we find the gravitational acceleration on the surface of the new planet:

And since , we find

Iread this book last year so take this with a grain of salt.gene jumps from the tree to compete with finny due to the fact that gene is always trying to do better than finny. he is put under the grasp of peer pressure due to finny almost forcing him to do this. ever since he first jumped finny kept pressuring him to jump since he thought gene enjoyed jumping.rather than uses this answer you should probably just reread chapters 3-4