How many numbers between 200 and 400 begin or end with 2?
How many numbers between 200 and 400 begin or end with 2?
Answer/Solution
110
Steps/Work
How many numbers between 200 and 400 begin or end with 2?
Just think that those numbers are:
i) The ones ending in 2: 202, 212, 222, ... , 392 --> 20 numbers
ii) The ones beginning in 3: 200, 201, 202, 203, ... , 293, ... , 299 --> 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 2: 202, 212, 222, ... , 392 --> 20 numbers
ii) The ones beginning in 3: 200, 201, 202, 203, ... , 293, ... , 299 --> 100 numbers
BUT 10 out of the first 20 numbers are repeated in the second set.
THEREFORE, the solution is 110 numbers.
Answer: D