Element X is a radioactive isotope such that every 12 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 900 grams, how much of the
element would remain after 6 years, to the nearest whole number?

The classrooms are trying to raise $1,200.00 for charity. mrs. leblanc's class has raised 50%. mr. patel's class has raised $235.14 ms. warner's class has raised 1/3 as much as mrs. leblanc's class. how much more money is needed to reach the goal of $1,200.00?

What is the perimeter of a rectangular building that is 80 feet wide and 140 feet deep?

Haruka hiked several kilometers in the morning. she hiked only 66 kilometers in the afternoon, which was 25% less than she had hiked in the morning. how many kilometers did haruka hike in all?