Solve for x in simplest rational form!! thx!

Antonia and carla have an equivalant percentage of green marbles in their bags of marbles. antonia has 4 green marbles and 16 total matbles. if carla has 10 green marbles , how many total marbles does carla have

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Donald has x twenty-dollar bills and 11 ten-dollar bill. how much money does donald have? write your answer as an expression.