Find the value of '?' if (50 - ?/29)% of 4200 equals 3 times the square root of 196.

Explanation

We need to determine '?' such that (50 - ?/29)% of 4200 is equal to 3 multiplied by the square root of 196. Since √196 = 14, 3 × 14 = 42. Therefore, (50 - ?/29)% of 4200 = 42. Solving this equation leads to the correct answer, which corresponds to option D: 1421.