The sum is 12x3+18x2-10x+8
Pattern P:
40, 38, 36, 34, 32, 30, …
Pattern Q:
40, 36, 32, 28, 24, 20, …
(absolute) Differences in corresponding terms:
0, 2, 4, 6, 8, 10, …
and these differences agree with the last statement.
Well, if we take 68.73 as the 100%, how much is 12 of it in percentage?
well

solve for "x"
If we have 156 beads and we can make one bracelet with 9 beads we divide 156 by 9 and get 17 1/3. since we cannot have 1/3 of a bracelet, we can make 17 bracelets.