You would need 20 nickels for 1 dollar and only 4 quarters for 1 dollar. Do 20 minus 4 and your answer is 16 nickels. The stack of nickels is 16 coins thicker. Hope this helped!
To solve, start with this equation So, 8 times 3 gives you how long they spent on art and 8 times 4 gives you how long they spent on science. So they spent... and...