John is painting a picture. He has green, red, yellow, purple, orange and blue paint. He wants to use four different colors on this picture. If order does not matter, how many ways can John pick four colors for his picture, if one of them is green?
a
6
b
15
c
10
d
4

c) 10

Step-by-step explanation:

You do 5 C 3 ( because you are choosing 3 from the remaining 5).

5C3 = 5!/(3!2!) = 10

C 10

Step-by-step explanation:

He has 6 colours to choose 3 from.

One of them is green, so he just needs to choose 2 from the remaining 5.

That's,

5C2 = 10

y=4

step-by-step explanation:

2^y = ln 5, or   y(ln 2) = ln 5.   solving for y,   y = (ln 5) / (ln 2).   y=5

step-by-step explanation: