Question

1. How many
numbers Can you make using the digits
2, 3, 4, 5, 9 (a without repeatation if digits)
(b with respitation of digits)​

Answer 1

$\displaystyle \huge\red{\underline{\underline{Solution}}}$

The number consists of 4 digits.

So the positions are

• Unit place

• Ten place

• Hundred place

• Thousand Place

The digits are 2, 3, 4, 5, 9

$\blacksquare \:$REPEATATION ARE ALLOWED

• Unit Place can filled in 5 ways

• Ten place can filled in 5 ways

• Hundred place can filled in 5 ways

• Thousand Place can filled in 5 ways

So the total numbers can be formed

$= 5 \times 5 \times 5 \times 5 = 625$

$\blacksquare$REPEATATION ARE NOT ALLOWED

• Unit Place can filled in 5 ways

• Ten place can filled in 4 ways

• Hundred place can filled in 3 ways

• Thousand Place can filled in 2 ways

So the total numbers can be formed

$\: = 5 \times 4 \times 3 \times 2 = 120$