9514 1404 393
Answer:
76
Explanation:
For some common difference d, the terms of the progression are ...
k = 3 +d
w = k +d = 3 +2d
18 = w +d = 3 +3d
Solving for d, we get ...
15 = 3d . . . . subtract 3
5 = d . . . . . . divide by 3
Now, we can find ...
3k +4w = 3(3 +d) +4(3 +2d) = 9 +3d +12 +8d = 21 +11d
3k +4w = 21 +11(5) . . . . substitute for d
3k +4w = 76