Question

Phil has 50 nickels and dimes worth $4.15. How many of each coin does he have?

Answer 1

$x-number\ of\ nickels\\50-x-number\ of\ dimes\\\\0.05x+0.1(50-x)=4.15\\0.05x+5-0.1x=4.15\\0.05x-0.1x=4.15-5\\-0.05x=-0.85\ \ \ \ |:-0.05\\x=17\\\\50-17=33\\\\He\ have\ 17\ nickels\ and\ 33\ dimes.$