Question

In how many ways can 3 postcards can be posted in 5 post boxes

Answer 1

5^3ways.

consider first post card.it can be posted in any of the 5 pboxes. so five ways.similarly for the second one and the third one.

Answer 2

Answer:

3 postcards can be posted in 5 post boxes in 10 ways.

Step-by-step explanation:

Given : No. of postcards = 3

           No. of post boxes = 5

To Find : In how many ways can 3 postcards can be posted in 5 post boxes

Solution:

To Find the number of possible ways we will use combination

Formula : $^nC_r=\frac{n!}{r!(n-r)!}$

n = 5

r = 3

Substitute the values

$^5C_3=\frac{5!}{3!(5-3)!}$

$^5C_3=\frac{5!}{3!(2)!}$

$^5C_3=\frac{5 \times 4 \times 3!}{3!(2)!}$

$^5C_3=\frac{5 \times 4}{2 \times 1}$

$^5C_3=10$

Hence 3 postcards can be posted in 5 post boxes in 10 ways.