Q. An element with mass 230 grams decays by 27.7% per minute. How much of the element is remaining after 8 minutes, to the nearest 1oth of a gram?Answer:
Understand and Determine Formula: Understand the problem and determine the formula to use.We know that the element decays by 27.7% per minute. This means that each minute, the element retains 100%−27.7%=72.3% of its mass from the previous minute. To find the remaining mass after 8 minutes, we will repeatedly apply the decay rate of 72.3%.
Convert Percentage to Decimal: Convert the percentage to a decimal to use in calculations. 27.7% as a decimal is 0.277, so the remaining percentage as a decimal is 1−0.277=0.723.
Calculate Remaining Mass (1 minute): Calculate the remaining mass after the first minute.Remaining mass after 1 minute = Initial mass × Remaining percentageRemaining mass after 1 minute = 230 grams ×0.723
Apply Decay Process (8 minutes): Perform the calculation for the remaining mass after the first minute.Remaining mass after 1 minute = 230×0.723=166.29 grams
Calculate Remaining Mass (8 minutes): Apply the decay process for 8 minutes.Since the decay happens each minute, we need to multiply the remaining mass by 0.723 for each of the 8 minutes.Remaining mass after 8 minutes = 230×(0.723)8
Perform Calculation (8 minutes): Calculate the remaining mass after 8 minutes.Remaining mass after 8 minutes = 230×(0.723)8
Complete Calculation and Round: Perform the calculation for the remaining mass after 8 minutes.Remaining mass after 8 minutes = 230×(0.723)8≈230×0.100258
Complete Calculation and Round: Perform the calculation for the remaining mass after 8 minutes.Remaining mass after 8 minutes = 230×(0.723)8≈230×0.100258Complete the calculation and round to the nearest 10th of a gram.Remaining mass after 8 minutes ≈230×0.100258≈23.05934 gramsRounded to the nearest 10th of a gram, the remaining mass is approximately 23.1 grams.