Question

How many numbers can be formed from 1, 2, 3, 4, 5 (without repetition), when the digit at the units place must be greater than that at the tens place? Key in the correct option number.

Answer 1

$\huge{\text{\underline{Question:-}}}$

How many numbers can be formed using all of 1,2,3,4,5(without repetition),when the digit at the units place must be greater than that in the tenth place?

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$\huge{\text{\underline{Solution:-}}}$

$\bigstar$Point to Remember:-

• when we take 1 as tenth place digit then in units place 2,3,4,5 can be used satisfying the condition.
• So left most three digits as it is non repetitive can be combined into 3! way.

Total number of ways = 4 × 3!

For 2 ⟹ 3 × 3!

For 3 ⟹ 2 × 3!

For 4 ⟹ 1 × 3!

Therefore,

Total number of ways will be = (4+3+2+1) × 3! = 60

$\large{\boxed{\text{Answer:-\:60}}}$

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