when the first digit of a 3 digit no.are interchanged,the value of the 3-digit no.reduce by 90.?

Question

how many such combination exist for the first two digit.pls help me

Answer 1

If you mean the first two digits are interchanged, then we can just ignore the third digit...

10 - 01 = 9
21 - 12 = 9
32 - 23 = 9
43 - 34 = 9
54 - 45 = 9
65 - 56 = 9
76 - 67 = 9
87 - 78 = 9
98 - 89 = 9

There are 9 possibilities.

Answer 2

i'm assuming you mean the first two digits of a 3 digit number, i.e. swapping the numbers in the 10s and the 100s place. let's see... 210s and 120s, 320s and 230s, ...., and 980s and 890s. 2,3,4,5,6,7,8,&9. that's 8 different possibilities for the first digit. and don't for get the negatives.

Answer 3

if you move the left side digit ..you will increase / decrease the # by 100 units/..
possible combinations with fist 2 Numbers 99.. if you swap the 0 wit 0 still get 0 as result you don't have 100 combinations but 99

Answer 4

let d hundreds digit=z
tens digit=y
units digit=x
acc. 2 ques: -

100z+10y+x-(100y+10z+x)=90
100z+10y+x-100y-10z-x=90
90z-90y=90
dividing both sides by 90
z-y=1
z=1+y
by hit nd trial method
we put one by one value of y, and we get d value of z

as we know y, being d tens digit of d no., can have only 10 values,i.e., 0 to 10.

==>there cn b only 10 such combinations.

Answer 5

Zero