Working independently X takes 12 hours to finish a certain work. he fi

Question

Working independently X takes 12 hours to finish a certain work. he finishes 2/3 of the work . The rest of the work is finished by Y whose rate is 1/10 th of X. In how much time does Y finsh his work?

A. 30 hours
B. 35 hours
C. 40 hours
D. 50 hours
E. 60 hours

Working independently X takes 12 hours to finish a certain work. he finishes 2/3 of the work . The rest of the work is finished by Y whose rate is 1/10 th of X. In how much time does Y finsh his work?

mongee23 · Accepted Answer

to makes sense logically, x completed 2/3 * 12 = 8 hours. remaining 4 hours.
Y will complete in: 4 x 10 (as y takes 10 times longer) = 40 hours

twobagels · Answer

X's rate is 1/12, and X finished 2/3 of the work.

Y's rate is 1/10th of X's rate, so x*(1/120) = 1/3

x=40.

C

MathRevolution · Answer

X rate of 1- day work:  \frac{1}{12}  and he finishes  \frac{2}{3}  of the work.

Reamining work:  1 - \frac{2}{3} = \frac{2}{3}

Y rate:  \frac{1}{10} * \frac{1}{12} = \frac{1}{120}

=>  \frac{1}{3}  work =  \frac{1}{120}  rate

=> Rate * Time= Work

=>  \frac{120 }{ 3}  = 40 hours.

Answer C

tarunrathi999 · Answer

Let Total work: 120 units
Speed of X: 10 units(since his rate is 12 hours to complete the work)
Speed of Y : 1 units per hour(1/10 of X)

Work Finished by X= 120*2/3=80
Work Left= 120-80=40

Time taken by Y
40/1= 40 hours

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

Working independently X takes 12 hours to finish a certain work. he fi

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

Working independently X takes 12 hours to finish a certain work. he fi

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards