Does anyone understand?? Consider the set {2, 1, 3, 4}. How many proper subsets could be formed from this set?

The diameter of a circular chip is doubled to use in a new board game. the area of the new chip will be

If the scale factor between two circles is 2x/5y what is the ratio of their areas?

Diane’s bank is offering 5% interest, compounded monthly. if diane invests $10,500 and wants $20,000 when she withdrawals, how long should she keep her money in for? round to the nearest tenth of a year.