#### Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Click to Chat

1800-1023-196

+91-120-4616500

CART 0

• 0
MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping

# If 'm' denotes th e no of 5-digit nos, if each successive digits are in their descending  order of magnitude and 'n' is the corresponding figure, when the digits are in their ascending order of magnitude then (m-n) has the value.....?

23 Points
11 years ago

Finding out the number of 5 digit numbers having digits in descending order:-

1)digits staring with 9--the next 4 digits can accommodate digits from 0 to 8 only.these can be selected in 9C4 ways and arranged in descending order and there is only one way of arranging the selected 4 numbers in descending order.

Eg:one of the sets formed is (8,0,3,5)

its descending order is 8530.the number is 98530.i.e.,only one way.

so number of 5 digit numbers formed are 9C4.

2)digits starting with 8--next 4 digits can have numbers from 0 to 7 only.these can be selected in 8C4 ways.

similarly digits starting with 7,6,5,4 gives 7C4+6C4+5C4+4C4.

m=9C4+8C4+7C4+6C4+5C4+4C4

Finding out number of 5 digit numbers having digits in ascending order:-

1)so,numbers starting with 1--next 4 digits can have digits from 2 to 9 only.so can be selected in 8c4 ways.

2)numbers starting with 2--7C4.

Similarly we can find numbers with 3,4,5

n=8C4+7C4+6C4+5C4+4C4

m-n=9c4=126