You have a 5 in 8 chance of getting a consonant originally. You should try to find an equal ratio except with 840 as the second number. As of now it's 5/8 = ?/840
8 is a factor of 840 and if you divide 840 by 8 you get 105. If you actually think about it 105/840 would be an equal ratio to 1/8 so you multiply 108 by 5 to get 525.
