How to multiply and simplify

If i have 20$ and i gave 5$ away how much i got

Pyramid shown has a square base that is 18 inches on each side has a surface area of 164 square inches what is the slant height

Aroulette wheel has 38 slots in which the ball can land. two of the slots are green, 18 are red, and 18 are black. the ball is equally likely to land in any slot. the roulette wheel is going to be spun twice, and the outcomes of the two spins are independent.the probability that it lands one time on red and another time on black in any order is(a) 0.5 (b) 0.25 (c) 0.4488 (d) 0.2244