Answer: 19
Step-by-step explanation:
Using the sum of an arithmetic series formula,
[tex]\sum^{30}_{n=2} (an+b)=2407 \implies 29(16a+b)=2407 \implies 16a+b=83\\\\\sum^{40}_{n=1} (an+b)=4220 \implies 20(41a+2b)=4220 \implies 41a+2b=211[/tex]
Multiplying the second equation by 2 gives us [tex]32a+2b=166[/tex].
Subtracting this from the second equation, we get that [tex]9a=45 \implies a=5[/tex].
Substituting this back into the first equation, we get that [tex]b=3[/tex].
Therefore, [tex]2a+3b=2(5)+3(3)=19[/tex]
