A circle has a diameter of 20 ft. What is the diameter? *

Since the question provided the diameter instead of radius, the diameter is 20 feet

well the diameter would be 20ft. If you meant to ask for the circumference then its 62.857ft

Step-by-step explanation:

Diameter of a circle is 20 feet.

Hence it's Radius = 20/2 = 10 ft

We know circumference = 2πr

Circumference = 2 × 22/7 × 10 ft

Circumference = 44 × 10/7= 440/7

Circumference = 62.857 ft

There are:

6 red balls - R5 black balls - BTotal number = 11 ballsA. Without replacement

i. Two blacks

P(BB) = 5/11*4/10 = 2/11

ii. The first is black

P(B) = 5/11

or, alternatively

P(BR or BB) = 5/11*6/10 + 2/11 = 3/11 + 2/11 = 5/11

iii. Both are of same colour

P(BB or RR) = 2/11 + 6/11*5/10 = 2/11 + 3/11 = 5/11B. With replacement

i. Two blacks

P(BB) = 5/11*5/11 = 25/121

ii. The first is black

P(B) = 5/11

or alternatively

P(BR or BB) = 5/11*6/11 + 25/121 = 30/121 + 25/121 = 55/121 = 5/11

iii. Both are of same colour

P(BB or RR) = 5/11*5/11 + 6/11*6/11 = 25/121 + 36/121 = 61/121