Final answer:
Kevin had 29 quarters and dimes, the total value of all the coins was $4.70, Kevin had 12 quarters.
Step-by-step explanation:
To find the number of quarters Kevin had, we need to set up an equation using the given information.
Let's assume Kevin had x quarters.
Since he had 29 quarters and dimes in total, we can set up the equation: x + (29 - x) = 29, where (29 - x) represents the number of dimes Kevin had.
The total value of all the coins was $4.70, so we can set up another equation using the values of quarters and dimes.
The value of x quarters is 25x cents, and the value of (29 - x) dimes is 10(29 - x) cents.
The equation for the total value is: 25x + 10(29 - x) = 470.
Simplifying the second equation, we get: 25x + 290 - 10x = 470.
Combining like terms, we have: 15x + 290 = 470. Subtracting 290 from both sides, we get: 15x = 180.
Dividing both sides by 15, we find x = 12.
Therefore, Kevin had 12 quarters.