Amount Invested by John in the savings account = $400 Rate of interest = 7% Time period for which the money is kept = 5 years Now the formula for calculating the amount of interest is I = P * R* T where I = Interest Amount P = Principal Amount R = rate of Interest T = Time for which the money is kept Now we know all the details within the formula, and so calculating the interest amount is easy. I = P * R * T = 400 * (7/100) * 5 = 400 * .07 * 5 = 2000 * .07 = 140 So the amount of interest that John will gain after 5 years is $140.
