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student\'s savings account has a balance of $3900 on September 1. Each month, th

ID: 3146833 • Letter: S

Question

student's savings account has a balance of $3900 on September 1. Each month, the balance declines by $450. Let B be the balance (in dollars) at t months since September 1.

Find the slope of the linear model that describes this situation. What does it mean in this situation?

The slope is         The balance declines by $

            per month.

b. Find the B-intercept of the model. What does it mean in this situation?

The B-intercept is        (Type an ordered pair.) The balance is $                   on September 1.

c. Find an equation of the model.

B=                     (Type an expression using t as the variable.)

d. Perform a unit analysis of the equation found in part c.

Choose the correct answer below.

A.

The unit of the expression on the left side of the equation is months, but the unit of the expression on the right side of the equation is dollars, which suggests that the equation is incorrect.

B.

The units of the expressions on both sides of the equation are months, which suggests that the equation is correct.

C.

The unit of the expression on the left side of the equation is dollars, but the unit of the expression on the right side of the equation is months, which suggests that the equation is incorrect.

D.

The units of the expressions on both sides of the equation are dollars, which suggests that the equation is correct.

e. Find the balance on April 1 (7 months after September 1).

$


Explanation / Answer

(a)

B(t) = 3900 - 450t

slope = -450

(b)

B-intercept is value of B at t = 0.

B-intercept = B(0) = 3900

(0,3900)

(c)

B(t) = 3900 - 450t

(d)

A.

The unit of the expression on the left side of the equation is months, but the unit of the expression on the right side of the equation is dollars, which suggests that the equation is incorrect.

False. both sides are dollars.

B.

The units of the expressions on both sides of the equation are months, which suggests that the equation is correct.

False. both sides are dollars.

C.

The unit of the expression on the left side of the equation is dollars, but the unit of the expression on the right side of the equation is months, which suggests that the equation is incorrect.

False. both sides are dollars.

D.

The units of the expressions on both sides of the equation are dollars, which suggests that the equation is correct.

False. both sides are dollars.

e. Find the balance on April 1 (7 months after September 1).

B(7) = 3900 - 450*7 = 750