Finance Interest Problems
Interest problems ask you to track how money grows or how debt accumulates over time. You'll work with simple interest (a fixed amount each period) and compound interest (interest earning interest), and the difference between the two is where most of the learning happens. A savings account growing at 4% compounded monthly behaves very differently from one earning 4% simple interest, and these problems teach you to quantify that difference. You'll also encounter loan amortization, comparing investment options, and figuring out how long it takes to double your money. This is one of the most directly practical categories — you'll use these skills every time you evaluate a mortgage, a car loan, or a retirement plan.Solve for the growth constant k using two data points. Write the exponential function A(t) for pandemic growth.
Find when population density reaches 1 person per square yard using exponential growth. 4.9% annual rate, 4.9M initial population.
Use kinematic equations to find vertical separation when a falling pot has different speeds at two heights.
Calculate remaining substance after given time using half-life formula. Solve exponential decay problems with clear examples and multiple solution methods.
Calculate impulse and force on passengers with different stopping times. Physics problem using momentum and Newton's laws.
Solve two-account investment problems. Find allocation between CD and bonds using system of equations.
Find how long it takes for money to double when compounded monthly at 13%. Use compound interest formula and logarithms.
Juggler catches a tossed ball: find time using quadratic equation and projectile motion.
Find girl's velocity relative to ice when she walks 1.5 m/s on a frictionless plank. Momentum conservation problem with reference frames.
Calculate max home price using $1,450/month mortgage at 8% over 30 years. Uses present value of annuity formula.