CAT Practice : Pipes cisterns, Work time

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Classic Work - Time Question!!

Mining

Q.18: A mining team made a plan to mine up to 300 m in a certain number of days. After working as per plan for 5 days, they added new members to the team and hence could mine 5 m more per day. In this way, 4 days before the planned date, they had mined 295 m. How many meters of mining was initially planned for each day?
1. 30 m
2. 12.5 m
3. 15 m
4. 7.5 m

Choice C. 15 m

Detailed Solution

Given, 295 m was mined out of which first 5 days – planned. Using option analysis:

a) $30 * 5 + (30 + 5) * (\frac{300}{30} – 5 – 4)$ = 150 + 35 x 1 = 185 ≠ 295

b) $12.5 * 5 + 17.5 * (\frac{300}{12.5} – 5 – 4)$ = 62.5 + 17.5 x 15 = 325 ≠ 295

c) $15 * 5 + 20 * (\frac{300}{15} – 5 – 4)$1 = 75 + 20 x 11 = 295

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More questions from Pipes Cisterns, Work Time

Mathematicians are creatures of habit. This topic has been called Pipes and Cisterns because someone named it like it long ago. Pipes and Tanks would be much better - at least makes it sound like wartime.