The tab types 450 words in 12 minutes. So first find the rate of typing. It is the number of words tab types in 1 minutes
Rate = 450 /12 = 37.5
It means tab types 37.5 words in 1 minute.
Now there are 2400 word paper to type. So total number of words to type is 2400
The minutes required to type 2400 words is
= Total number of words to type / number of words typed in 1 minute
=2400/ 37.5
=64
It will take 64 mire minutes to complete typing of 2400 word paper