Ethan has 12 coins. There are three 10p coins and nine 20p coins 20p coins. Ethan chooses 3 coins at random. Work out the probability that he takes exactly 50p.​

3/220.

Step-by-step explanation:

To get exactly 50p he must take 2 20p coins and 1 10p coin.

There are 3! /2! = 3 ways of doing this.

Total number of ways of getting any 3 coins form 12 is 12!/9!3!

= 12*11*10 / 3!

=  220.

So the answer is 3/220.

d, x=8

step-by-step explanation:

simplifying

4x + -5 = 2x + 11

reorder the terms:

-5 + 4x = 2x + 11

reorder the terms:

-5 + 4x = 11 + 2x

solving

-5 + 4x = 11 + 2x

solving for variable 'x'.

move all terms containing x to the left, all other terms to the right.

add '-2x' to each side of the equation.

-5 + 4x + -2x = 11 + 2x + -2x

combine like terms: 4x + -2x = 2x

-5 + 2x = 11 + 2x + -2x

combine like terms: 2x + -2x = 0

-5 + 2x = 11 + 0

-5 + 2x = 11

add '5' to each side of the equation.

-5 + 5 + 2x = 11 + 5

combine like terms: -5 + 5 = 0

0 + 2x = 11 + 5

2x = 11 + 5

combine like terms: 11 + 5 = 16

2x = 16

divide each side by '2'.

the diameter is 16 cm. are you a teacher?

step-by-step explanation: