Question

there are nine two-digit numbers with distinct tens digit. the unit digit number is ones less than its tens digit. find the average of units digit​

Answer 1

Answer:

Let the two no.s be a,b

Given,

a>b

(a+b)=2(a−b)

⟹a=3b

Put values of b such that a<10 (otherwise it would be a 3 digit number)

b=1,2,3

a=3,6,9

So, the possible numbers are 31,62,93.

Hence, 3 such numbers are possible.

Answer 2

Answer:

Step-by-step explanation:

As stated in the question that all the tens digits are distinct and the unit digit number is one less that the tens digit so we can say that

a>b & a-b=1.

so the possible number as per the given conditions can be:

10,21,32,43,54,65,76,87 & 98.

So the average of the unit digits will be 4.