Subject :IMO Class : Class 4
Ans 1:
Class : Class 4
ans a-80. From 1-9 there are 9 digits . so we are left with 151-9=142 digits. Note that from 10 onwards all numbers are of 2 digits. So there are 142/2=71 numbers to have 142 digits. Therefore there are 9+71=80 numbers.