How many numbers between 300 and 500 begin or end with 3?
How many numbers between 300 and 500 begin or end with 3?
Answer/Solution
110
Steps/Work
How many numbers between 300 and 500 begin or end with 3?
Just think that those numbers are:
i) The ones ending in 3: 303, 313, 323, ... , 493 --> 20 numbers
ii) The ones beginning in 3: 300, 301, 302, 303, ... , 393, ... , 399 --> 100 numbers
BUT 10 out of the first 20 numbers are repeated in the second set.
THEREFORE, the solution is 110 numbers.
Answer: D
Just think that those numbers are:
i) The ones ending in 3: 303, 313, 323, ... , 493 --> 20 numbers
ii) The ones beginning in 3: 300, 301, 302, 303, ... , 393, ... , 399 --> 100 numbers
BUT 10 out of the first 20 numbers are repeated in the second set.
THEREFORE, the solution is 110 numbers.
Answer: D