This is another easy 10G...
a) Go to the "Play Now" option at the main menu screen.
b) Set your team to an overall "C" team(It can be "D" also), you can find some in the "Patriot League" and others, but it doesn't matter what team you will choose.
c) Set the CPU's team to an overall "A" team, you can find some of these teams in "Pac-10" or "Big East" and others, but again, it doesn't matter.
d) Go to "Game Settings" after you have selected the teams, and change the difficulty to "All-Conference" and the time per half to "2"
Also go to "Gameplay Settings" and then to "User Settings" and slide the "Long Range Shooting" slider to 100.
e) Just shoot threes the whole game, just make sure before you shoot, your player has some space in front of him preventing the block.
f) Once you have defeated the CPU, the achievement should pop up and you should unlock your easy 10G!