Final answer:
The value of (3 u 8) + (8 n 3) is found by applying the given operation definitions, resulting in 95 + 65, which equals 160. Therefore, the answer is option C.
Step-by-step explanation:
To find the value of (3 u 8) + (8 n 3), we need to use the given definitions for the operations 'u' and 'n':
- mun = 5m + 10n
- mn n = 10m - 5n
Substitute m=3 and n=8 into the first equation:
3u8 = 5×3 + 10×8 = 15 + 80 = 95
Substitute m=8 and n=3 into the second equation:
8n3 = 10×8 - 5×3 = 80 - 15 = 65
Now, add the results together:
(3u8) + (8n3) = 95 + 65 = 160
Therefore, the correct answer is 160, which corresponds to option C.