Question 329315
(a) Solve the formula for R.  Leave the answer simplified.


We need to isolate R.  In other words, we need to place R all alone on one side of the equation.  Thisis what is meant by solve for R.

A = P(1 + Rt)

A = P + RPt

A - P = RPt

(A - P)/Pt = R

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(b) What rate of interest are you earning if in 5 years your $6,000 investment has grown to be $7,140?

We need to use the given formula.

A = P(1 + Rt)

Let A = 7140

Let R = rate of interest

Let P = 6000

Let t = 5

We now plug into formula and simplify.

7140 = 6000(1 + R5)

7140 = 6000 + 30000R

7140 - 6000 = 30000R

1140 = 30000R

1140/30000 = R

0.038 = R

3.8% = R