How many black keys would you expect to find on a keyboard with 72 keys in all

Lance lived in portugal and brazil for a total of 14 months to learn portuguese. he learned an average of 130 new words per month when he lived in portugal, and an average of 150 new words per month when he lived in brazil. in total he learned 1920 new words. write a system of equations to represent the situation. use x to represent portugal, and y to represent brazil

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?

Nicole is making carrot bread she needs 5 cups of carrots for 2 cups of sugar. what is the ratio of cups of sugar to cups of carrots that nicole will need? write the ration in three different ways