The first six triangular numbers (1, 3, 6, 10, 15, 21) are printed one each on one

Question:

The first six triangular numbers (1, 3, 6, 10, 15, 21) are printed one each on one side of a card. The cards are placed face down and mixed. Choose two cards at random, and let x be the sum of the two numbers. Construct the probability distribution for this random variable x.

Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...