Mary and her brother john collect foreign coins. mary has 3 times the number of coins that john has. together they have 180 foreign coins. find how many coins mary has.

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.

Awasher and a dryer cost $701 combined. the washer costs $51 more than the dryer. what is the cost of the dryer?

Solve for n. round to the tenths place, if necessary. 14.2 cups of flour6 loaves of bread= 20 cups of flour n