#81 Calculating average speed from distance and time
#84 Calculating y by inserting x into a formula
#89 Total interest paid using compound interest formula
#222 Solving for time using distance and speed
#223 Calculating the simple interest earned
#224 Money owed to a bank adding compound interest
#244 Calculating the number of litres needed to travel a given distance
#245 Ratio of boys to girls in a classroom
#246 Direct vs indirect proportion
#247 Calculating the number of periods to earn a given interest
#248 Calculating the final amount after investing with compound interest
#321 Accumulated amount after inflation