Answer:
No, because the bike order does not meet the restrictions of 6c + 4a ≤ 100
Explanation:
It is given that, each child bike requires 4 hours to build and each adult bike requires 6 hours to build.
Hence, c child bikes and a adult bikes require
hours to build.
It is also given that, each child bike requires 4 hours to test and each adult bike requires 4 hours to test.
Total time to test, c child bikes and a adult bikes is

The company will be able to make c child bikes and a adult bikes if

If c = 20 and a = 6, then (4c + 6a) = 116 < 120.
and (4c + 4a) = 104 > 100.