Pls solve the first 2 :>

Pls! does anybody know a shortcut for answering these types of questions in the future?

9/10 divide by -3/15 as a mixed number

Someone answer asap for ! the following statements are true about the coins calvin and sasha have collected. * calvin and sasha has the same amount of money. * calvin has only quarters. * sasha has dimes, nickels, and pennies * calvin has the same number of quarters as sasha has dimes. * sasha has $1.95 in coins that are not dimes. exactly how many quarters does calvin have?