A newly discovered radioactive isotope has a half-life of 2 minutes. Scientists isolated a sample of this isotope and measured its initial mass. After 10 minutes, 12.5 g of the isotope was left. What was the initial mass? need the answer asap! thanks

50 ! pls ! 12.  building codes regulate the steepness of stairs. homes must have steps that are at least 13 inches wide for each 8 inches that they rise.

a. discuss how to find the slope of the stairs.
b. describe how changing the width or height affects the steepness of the stairs.

Michael split a rope that was 28 inches long into 5 equal parts. brenden split a rope that was 30 inches long into 6 equal parts. which boy's rope was cut into longer pieces?

Andy has $310 in his account. each week, w, he withdraws $30 for his expenses. which expression could be used if he wanted to find out how much money he had left after 8 weeks?