Answer
$3.50
Work Step by Step
Interest = $ principal \times rate \times time$
Principal = 400
rate = $3\frac{1}{2}$ % = 3.5% = 0.035
time = 3 months = $\frac{3}{12} years = \frac{1}{4}$ years
Interest = $ 400 \times 0.035 \times \frac{1}{4}$ = 3.50 Dollars
