Answer:
358
Step-by-step explanation:
If we multiply the first equation by 3 on both sides we get 3a+3b=243.
If we multiply the second equation by 5 on both sides we get 5b+5c=115.
Adding these equations gives
(3a+3b)+(5b+5c)=243+115
Combine like terms:
3a+8b+5c=358
Another way.
Find numbers to satisfy the criteria.
a+b=81
b+c=23
Choose a=80.
This forces b=1 since 80+1=81.
If b=1 and b+c=23, this forces c=22.
Now plug into 3a+8b+5c.
3(80)+8(1)+5(22)
240+8+110
358
