Question

HOW MANY 7 DIGIT TELEPHONE NUMBERS ARE POSSIBLE IF THE FIRST DIGIT CANNOT

BE ZERO AND:
1) THE TELEPHONE NUMBER MUST BE A MULTIPLE OF 100?
2) ONLY ODD DIGITS CAN BE USED?
3) THE FIRST 3 DIGITS ARE 277?

Answer 1

there are 8 million different phone numbers whose phone numbers whose digits aren't 0 or 1