A collection of nickels and dimes is worth 25 dollars. There are twice as many nickels as dimes. How many of each are there? Use let statements and solve algebraically. May I please get an explanation too?

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.

Which of the following circles have their centers in the third quadrant?

Benefit(s) from large economies of scale, in which the costs of goods decrease as output increases. natural monopolles perfect competition