Let 3, 6, 9, 12, upto 78 terms and 5, 9, 13, 17, upto 59 terms be...

Given,

$3, 6, 9, ⋯$ upto $78$ terms

$⇒ {t}_{78} = 3 + 77 \times 3 = 234$

$5, 9, 13, ⋯$ upto $59$ terms

$⇒ {t}_{59} = 5 + 58 \times 4 = 237$

Common difference of common terms $= LCM\left\{3, 4\right\} = 12$

First common term is $9$ and last common term is $225$

So series will be $9, 21, 33, ⋯ , 225$ $⇒ n = 19$

$S = \dfrac{n}{2}\left[a + l\right] = \dfrac{19}{2}\left[9 + 225\right] = 2223$