Jean has 5 different colors of markers: red, blue, green, orange, and purple. Two colors are used to make a sign. How many different combinations are possible? List them.
We need to find the number of possible combinations of r objects from a set of n objects. Jean has 5 different colors which means that n=5 and 2 colors are used to make a sign, which means r=2. The number of combinations can be calculated with the formula: C=n!/((n-r)!r!) C=5!/(5-2)!*2! C=5*4*3!/3!*2*1 C=20/2=10 The possible combinations are: 1.red blue 2.red green 3.red orange 4.red purple 5. blue green 6. blue orange 7. blue purple 8. green orange 9. green purple 10. orange purple