Solve Simple Interest Applications: example 6.34

Find the principal invested if $$178$ interest was earned in $2$ years at an interest rate of $4%.$

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Find the principal invested if $$495$ interest was earned in $3$ years at an interest rate of $6%.$

How did it go?

Write the formula.	$I = P r t$
Substitute the given information.	$178 = P (0.04) (2)$
Divide.	$\frac{178}{0.08} = \frac{0.08 P}{0.08}$
Simplify.	$2,225 = P$
Check your answer. Is it reasonable that $2,225 would earn $178 in 2 years?
$I = P r t$
$178 \overset{?}{=} 2,225 (0.04) (2)$
$178 = 178 ✓$
Write a complete sentence that answers the question.	The principal is $2,225.

Write the formula.	$I = P r t$
Substitute the given information.	$178 = P (0.04) (2)$
Divide.	$\frac{178}{0.08} = \frac{0.08 P}{0.08}$
Simplify.	$2,225 = P$
Check your answer. Is it reasonable that $2,225 would earn $178 in 2 years?
$I = P r t$
$178 \overset{?}{=} 2,225 (0.04) (2)$
$178 = 178 ✓$
Write a complete sentence that answers the question.	The principal is $2,225.