Hello!
If you invest 34,100$ into an account that has 4% simple interest, and because you want a balance of 38,192$ well I'll explain it first.
34,100$ x 4% = 1364
take 1364 x 4% = 56.54
we are almost at the answer,
lets go back to the question.
take 34,100$ - 38,192$ = 4092, now take 56.54 divided by 4092 = 12
12 is your answer!