No, 8 cannot go into 42 evenly.
Seven times.
Factors of 42 are 1, 2, 3, 6, 7, 14, 21, and 42
7 goes into 28 4 times
The answer will depend on whether the length is 42 inches, 42 feet or even 42 miles!
42
42-8 = 34
8
20 does not wholly go into 42. However, excluding remainders, it goes into 42 two times.
42 ÷ 21 = 2
300 divided by 42 = 7.1428571
42 x 8 = 336