Three trolley tours leave from the same stop at 9:00 am. Tour A returns to the stop every 75 minutes, Tour B returns every 60 minutes, and Tour C returns every 40 minutes. In how many hours will all three tours return to the stop at the same time?

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

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.

If a=0.333333 and b=0.55555, what is the value of a+b