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Barkatis
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Here is the way I solve it using the formula RATE = JOB / TIME

Let x be the Job done by Jack in one hour and y the job done by Johon in one hour.

Working together, John and Jack can type 20 pages in one hour : x/1 + y/1 = 20/1

they would be able to type 22 pages in one hour if Jack increases his typing speed by 25%: 5/4(x/1) + y/1 = 22/1

Thus x=8 ; y=12
x/y = 2/3
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Let the rate of John be x pages per hour and the rate of Jack y pages per hour.

so x + y = 20------------(i)
After 25% increase by y
x + 1.25y = 22-----------(ii)
Solving i and ii
y = 8
x = 12
Ratio = 2/3
Ans. D
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x+y=20
4x+5y=88
x=8
y=12

==>D
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Let the Rate of John = a & Rate of Jack = b

Let the combined time taken = t

(a+b)t = 20 ............... (1)

25% increase in rate of Jack \(= \frac{125b}{100}\)

\((a + \frac{125b}{100})t = 22\) ......... (2)

\(\frac{a+b}{a+1.25b} = \frac{10}{11}\)

\(\frac{b}{a} = \frac{2}{3}\)

Answer = D
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Barkatis
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?

A. 1/3
B. 2/5
C. 1/2
D. 2/3
E. 3/5

so we are told that Jack's 25% typing speed contributes 2 pages , 100% speed would contribute 8 pages in an hours. So JACK types 8 Pages
and JOHN types 12 Pages in an hour time.

Ratio of their speed :
\(\frac{8}{12} = \frac{2}{3}\)
Answer D
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Jack + John = 20 per hour
Jack increase 25% = 22 per hour
25% = 2
100% = 8
Jack 100% = 8 per hour

20 - 8 = 12 per hour

John = 12 per hour
Jack = 8 per hour

8 / 12 =
2 / 3
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Signature VeritasPrepKarishma move: If 2 is 25% of a number, the number is 8 and therefore, the new ratio is 10:12 and the old ratio 8:12 = 2:3
:)
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We're told John and Jack can type 20 pages in one hour.

Let John = J
Jack = A

J + A = 20
J + 1.25A = 22

IF .25A = 2, then A = 8. If A = 8, then J = 12.

8: 12
2 : 3

Answer is D.
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Hi, I tried solving this question using the conventional approach, please tell what's wrong.

Rate of John = 1/John and Rate of Jack = 1/Jack.

Equation 1: 1/John + 1/Jack = 1/20 (Combined Rate)
Equation 2: 1/John + 1/1.25 Jack = 1/22 (Combined Rate)

By subtracting Equation 2 from 1 we get Jack = 44 and John = 3/110. Please advise what went wrong.
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