Question

A number plate has 3 digits .If first digit is always 1 and rest two digits are in ascending order. Total number of different numbers that can be given the number plate

Answer 1

165 is the answer? please tell if its correct. if it is I will send the method

Answer 2

28

First position is set to 1.

Next two positions are remaining and it is provided that those two numbers are in ascending order.

So, first case:

123,124,125,126... 7 possibilities

134,135,136,137... 6 possibilities

and similarly, 7+6+5+4+3+2+1