how would you solve this one ?
Working together, John and Jack can type 20 pages in one hour. If they would be able to type 22 pages in one hour if Jack increases his typing speed by 25%, what is the ratio of Jack's normal typing speed to that of John?
Lets say John types x pages an hour and Jack types y pages an hour.
We know that x+y=20
Jack increase speed by 25% means he will type 1.25y pages an hour.
So we get x+1.25y=22
We need to know the ratio of Jack's speed to John's speed. This is going to be proportional to the number of pages each can type in an hour, hence (y/x).
Subtracting both : 0.25y=2 so y=8 ... so x=12
(y/x)=2/3Answer is (D)
1) Algebra-101 2) Sequences 3) Set combinatorics 4) 3-D geometry
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