The correct answer is (d). If d represents the number of dimes and q the number of quarters, the total number of coins would be d+q, which is given as 40 in the prompt: d+q=40
Since each dime is worth ten cents and each quarter worth twenty-five cents, their total value would be 0.10d+0.25q which would total 5.80.: 0.10d+0.25q=5.80 I HOPE THIS HELPS YOU