Mary has 3 times the number of coins john has. together they have 180 coins. how many coins does Mary have?
Let x = the number of coins that John has
Then, Mary has x times 3 coins
From the problem statement, we know that x + 3x = 180; 4x = 180; x = 45.
Thus, John has 45 coins and Mary has 45 x 3 = 135 coins.
