Question

UNDERSTANDING ISC MATHEMATICS - XI
How many numbers consisting of five different digits can be made from the digits 1, 2, 3,
9 if
(i) the number must be odd
(ii) the first two digits of each number are even?
Solve problem 16 if repetition of digits is allowed.
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Answer 1

1)-- 8400 because there are total 5 odd number we fix the 5 in first digit then remaining no from total are 8 then 7 then 6 then 5 i.e.

5*8*7*6*5

2)-- 2520 because there are total 4 even numbers at first place we put 4 so the remaining even numbers are 3 then from total we got 7 then 6 then 5

4*3*7*6*5