5B Test Review

The population of a city increases by 3% every year. If its population is 225,000, what will its population be in 4 years?

• 225,000 ⋅ (0.03)

• 225,000 ⋅ (1.03)

• 225,000 ⋅ (1.03) ⋅ (4)

• 225,000 ⋅ (1.03)⁴

At the beginning of the year, the number of books owned by a library was 15,000. Since then, it has grown by 3% each month. Which expressions represent the number of books , in thousands, owned by the library 4 years later if it continues to grow at the rate? (SELECT ALL THAT APPLY)

• 15 ⋅ ((1+0.03)¹²)⁴

• 15 ⋅ ((1+0.03)¹²)⁴⁸

• 15 ⋅ (1.03)⁴

• 15 ⋅ (1.03)⁴⁸

• 15 ⋅ (0.03)⁴⁸

For which function does f decrease by 25% every time x increases by 1?

• f(x) = 0.25^x

• f(x) = 0.75^x

• f(x) = 25^x

• f(x) = 85^x

The function  c(x) = 50 ⋅ (1.08)^x models the cost in dollars, c, of 1 ounce of a certain chemical used in a laboratory.  x represents the number of years since 2005.

Does the cost of the chemical increase of decrease over time, and by what percentage per year does it do so?

• increase by 8%

• decrease by 8%

• increase by 92%

• decrease by 92%

The function  c(x) = 50 ⋅ (1.08)^x models the cost in dollars, c, of 1 ounce of a certain chemical used in a laboratory.  x represents the number of years since 2005.

How much does an ounce of the chemical cost in 2024?

(round appropriately for the money amount)

• $215.79

• $233.05

• $317.06

• $293.57

Someone is gifting you with money from a savings account on your 16th birthday.

The savings account started with $500 and grows each year by $50. Which function represents this savings account?

• y = 50x+500

• y = 500x + 50

• y = 500(1.50)^x

• y = 500 ⋅ (50)^x

Someone is gifting you with money from a savings account on your 16th birthday.

The savings account started with $500 and grows by 8% each year. Which function represents this savings account?

• y = 8x+500

• y = 500x + 8

• y = 500(1.08)^x

• y = 500 ⋅ (0.92)^x

Which formula defines the sequence 1, 4, 7, 10, 13, 16...

• a₁ = 1 , a_n = 4 + a_n-1

• a₁ = 1 , a_n = 1 + a_n-1

• a₁ = 1 , a_n = 3 + a_n-1

• a₁ = 6 , a_n = 4 + a_n-1

A sequence is defined by a₁ = 5 and a_n = 3 ⋅ a_n-1

Which of the following statements defines the n^th term of a?

• a_n = 5 + 3(n-1)

• a_n = 3 + 5n

• a_n = 5 ⋅ 3^n-1

• a_n = 5 ⋅ 3ⁿ

Here are some values of the sequence , Write a recursive definition (formula) for the sequence.

3, 9, 27...

(remember recursive helps you find the next term)

• a_n = a_n-1 + 3

• a_n = 3 + 3(n-1)

• a_n = 3 (a_n-1)

• a_n = 3 ⋅ 3^n-1