A money bag has twenty 1-dollar coins and thirty 2-dollar coins.A coin is randomly selected from the bag.What is the probability of selecting a 2-dollar coin?[Give your answer as a decimal.]

The ratio of the number of twenty-cent coins to the number of one-dollar coins in a bag was 5 : 12 at first.Jerry took 10 one-dollar coins from the bag and exchanged them for twenty-cent coins.He then put the twenty-cent coins back into the bag.The ratio of the number of twenty-cent coins to the number of one-dollar coins in a bag became 3 : 2.How many twenty-cent coins were there in the end?

In a bag, there are coins of 25 p, 10 p and 5 p in the ratio of 1 : 2 : 3. If there are Rs.30 in all, how many 5 p coins are there ?

Bob has n coins in his pocket. One is two-headed, the rest are fair. A coin ispicked at random, lipped, and shows heads. Find the probability that the coinis two-headed

Katie had 21 nickels, dimes and quarters worth $2.25. If she had twice as many nickels as quarters, how many of each type of coin did Katie have?

Suppose you have a cookie jar that contains 13 chocolate chip cookies and 24 oatmeal cookies. If you reach in the jar and pull out 2 cookies at random, find the probability that both are chocolate chip. Express answer to two decimal places.