Answer :

Answer:

- The first bike costs \( \boxed{172} \) dollars.

- The second bike costs \( \boxed{860} \) dollars.

Step-by-step explanation:

Let's solve this problem step by step.

Let the cost of the first bike be \( x \).

Let the cost of the second bike be \( 5x \).

From the problem statement, we know that the cost of the second bike (5x) is $688 more than the cost of the first bike (x). Therefore, we can write the equation:

\[ 5x = x + 688 \]

Now, solve for \( x \):

\[ 5x - x = 688 \]

\[ 4x = 688 \]

\[ x = \frac{688}{4} \]

\[ x = 172 \]

So, the cost of the first bike \( x \) is $172.

Now, calculate the cost of the second bike (5x):

\[ 5x = 5 \cdot 172 \]

\[ 5x = 860 \]

Therefore, the cost of the second bike \( 5x \) is $860.

To verify:

- The cost of the second bike (5x) is indeed $688 more than the cost of the first bike (x):

 \[ 860 - 172 = 688 \]

Hence, everything checks out correctly. The cost of the bikes are:

- The first bike costs \( \boxed{172} \) dollars.

- The second bike costs \( \boxed{860} \) dollars.