Combinations

Find the number of ways in which 3 components can be selected from a batch of 20 different components

• 6840

• 1140

• 402

• none of the above

In how many ways can a group of 4 boys be selected from 10 if the oldest boy is included in each group

• 84

• 81

• 504

• 6

In how many ways can a group of 4 boys be selected from 10 if the oldest boy is excluded

• 32

• 14

• 504

• 126

₂₀C₁₈

• 0
• 1
• 190
• 1140

Picking a team of three people out of a group of 10.

• Permutation
• Combination
• Neither

In a Combination, Order Matters.

• True
• False

4 letters are chosen at random from the word RANDOMLY. In how many ways can this selection be made?

• 24

• 1680

• 70

• 40320

• 438

What is the formula for Combinations?

• ^n!∕_(n-r)! r!
• ^n!∕_(n-r)!
• ^r!∕_{(r-n)! n!}
• n!

Evaluate ₁₀C₁

• 5
• 10
• 15
• 20

Evaluate ₁₂C₁₂

• 1
• 10
• 100
• 1000