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? (a)54(b)40(c)60(d)48(e)36

Answer 1

Answer:c

Step-by-step explanation:

place 2,3,4,5 can be used satisfying the condition.

so leftmost three digits(as it is non repetitive)can be combined into 3! way

total ways=4*3!

for 2=>>3*3!

for 3=>>2*3!

for4=>>1*3!

therefore total numbers will be=(4+3+2+1)*3!=60

option (c) is correct