This is a good example of permutations. For the first slot on his shelf, Dylan has 7 trophies to choose from. Then 6, 5, and so on. Since he is only fitting 4 trophies on his shelf, we only continue until we have the slots filled. Thus, we have $7\cdot 6 \cdot 5\cdot 4=\boxed{840\:\text{ways}}$ to do so.

*Note: We do not divide by $4!$ because in this case, order matters. A different order of the same four books still produces different arrangements, so the order matters.

6 0

3 years ago

60% of the class is making a C or higher. If 21 students are making a C or higher, how many students are in class?

omeli [17]

Answer:

around 33 students.

Step-by-step explanation:

6 0

3 years ago

Independent and Dependent events

Vanyuwa [196]

There are 3 cards and only 1 card is off.

If you pick the odd card first and do not replace it there is no chance of picking a second odd card.

The probability would be 0

4 0

2 years ago