Answer:
45
Step-by-step explanation:
The order in which the items are chosen is not important. So we use the combinations formula to solve this question.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.

How many possible subsets of 2 items can be chosen from this lot?
Combinations of 2 from a set of 10. So

First, distribute the (1/2) into (4x+12) by multiplying them.
The equation becomes:
2x + 6 + 5x = 30
On the left side, combine “like terms” through addition.
7x + 6 = 30
Subtract 6 from both sides:
7x = 24
Finally, get x alone by dividing both sides by 7:
x = 24/7, or if you wanted to round the decimal answer, it’s about 3.429.
I think it's 20. Sorry if it's wrong