Quantitative Literacy Test 2 Prep
independent variable - Answer-a variable (often denoted by x ) whose variation does not depend on that
of another.
dependent variable - Answer-a variable (often denoted by y ) whose value depends on that of another.
Linear Model - Answer-A linear function representing real-world phenomena. The model also represents
patterns found in graphs and/or data.
exponential model - Answer-a model of population growth in which a constant and unlimited growth
rate results in geometric increases in population size
1. The population of Happy Town is growing at a rate of 5% per year. In 2000, there are 100 people in
Happy Town, how many live there in 2020? - Answer-1. a) Indep: # of years since 2000, t; dep:
population, P; b)
c) P(20)=100(1.05)20=265.33≈265 people.
2. Every year since 1975, the population of Shrink Town is decreasing by 20 people. In 1975, the
population was 1500. When will the population of Shrink Town reach zero? - Answer-2. a) Indep: # years
since 1975, t; dep: population , P; b) P(t)=1500 - 20t;
c) 0=1500 - 20t; t=75 years - 2050 the population will be 0.
3. In 2050, there are 5000 people living on Mars. In 2060, there are 6500 people living on Mars. The
population of Mars in increasing at a constant rate. How many people are living on Mars in 2075? -
Answer-3. a) Indep: # years since 2050, t; dep: population of Mars, M; b) (0,5000) & (10,6500);
M(t)=150t+5000; c) M(25)=150(25)+5000=8750 martians
independent variable - Answer-a variable (often denoted by x ) whose variation does not depend on that
of another.
dependent variable - Answer-a variable (often denoted by y ) whose value depends on that of another.
Linear Model - Answer-A linear function representing real-world phenomena. The model also represents
patterns found in graphs and/or data.
exponential model - Answer-a model of population growth in which a constant and unlimited growth
rate results in geometric increases in population size
1. The population of Happy Town is growing at a rate of 5% per year. In 2000, there are 100 people in
Happy Town, how many live there in 2020? - Answer-1. a) Indep: # of years since 2000, t; dep:
population, P; b)
c) P(20)=100(1.05)20=265.33≈265 people.
2. Every year since 1975, the population of Shrink Town is decreasing by 20 people. In 1975, the
population was 1500. When will the population of Shrink Town reach zero? - Answer-2. a) Indep: # years
since 1975, t; dep: population , P; b) P(t)=1500 - 20t;
c) 0=1500 - 20t; t=75 years - 2050 the population will be 0.
3. In 2050, there are 5000 people living on Mars. In 2060, there are 6500 people living on Mars. The
population of Mars in increasing at a constant rate. How many people are living on Mars in 2075? -
Answer-3. a) Indep: # years since 2050, t; dep: population of Mars, M; b) (0,5000) & (10,6500);
M(t)=150t+5000; c) M(25)=150(25)+5000=8750 martians
