The diameter of a circle is found by doubling the radius. Write a formula for the diameter of a circle, d, of its radius, r.​

Me n o w. i need t h i s. 10 points

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

If t17 = 3 (t5) in an arithmetic progression, find t1 in terms of d.