CAT 2021 Question Paper | Quant Slot 1

CAT Questions

CAT 2021 Quant was dominated by Arithmetic followed by Algebra. In Arithmetic, the questions were dominated by topics like Speed-time-distance, Mixture and Alligations. This year, there was a surprise. The questions from Geometry were relatively on the lower side as compared to the previous years. There were 8 TITA Qs this year. Overall this section was at a medium level of difficulty.

Question 19 : Anu, Vinu and Manu can complete a work alone in 15 days, 12 days and 20 days, respectively. Vinu works everyday. Anu works only on alternate days starting from the first day while Manu works only on alternate days starting from the second day. Then, the number of days needed to complete the work is

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Video Explanation

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Explanatory Answer

Anu can do \\frac{1}{15}) of work in one day.
Vinu can do \\frac{1}{12}) of work in one day.
Manu can do \\frac{1}{20}) of work in one day.
On the odd days, Anu and Vinu work together. They together can do \\frac{9}{60}) of work in one day.
On the even days, Manu and Vinu work together. They together can do \\frac{8}{60}) of work in one day.
\\frac{9}{60}) + \\frac{8}{60}) + \\frac{9}{60}) + \\frac{8}{60}) + \\frac{9}{60})+ \\frac{8}{60}) + \\frac{9}{60}) = \\frac{60}{60})
Therefore, the work was completed in 7 days.

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The answer is '7'

Choice D is the correct answer.