Can somebody tell me how to do this problem?
The yearly changes of population of a city for three consecutives years are, respectevely, 20% increase, 30% increase, and 20% decrease. What is the total percent change from the beggining to the end of the third year?
2006-09-11 11:29:25 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
1 * 1.2 * 1.3 * .8 = 1.248 Thus you have a 24.8% increase from the beginning to the end of the third year. The 1.2 is the 20% increase, the 1.3 is the 30% increase and the .8 is the 20% decrease (1 - .2 = .8).
2006-09-11 11:32:37 · answer #1 · answered by maegical 4 · 0⤊ 0⤋
1 .2 X 1.3 = 1.56
1.56X .8=1.248 so about a 25% increase
2006-09-11 18:45:49 · answer #2 · answered by MollyMAM 6 · 0⤊ 0⤋
The original population is 100%, or 1.
After 1 year, it increases 120%, or 1.2.
After 2 years, it is 130% of 120%, or 1.2 * 1.3 = 1.56.
After 3 years, it is 120% of 156%, or 1.2 * 1.56 = 1.872, an 87.2% increase.
2006-09-11 18:38:37 · answer #3 · answered by menezes_dean 2 · 0⤊ 1⤋
After year 1, it's 1.2. 1.2*1.3=1.56, 1.56*0.8=1.248, therefore, the population increased 24.8%
2006-09-11 18:50:43 · answer #4 · answered by Bob Smith 5 · 0⤊ 0⤋