Find the total output of a coal mine if after 14% wastage, the net out

1.	Find the total output of a coal mine if after 14% wastage, the net output is 68,400 quintals.In a class of 740 students, 10% students secured first division, 15% students secured secoand 10% were just passed. What per cent of students failed?obtained by
Answer» ANSWER: A) Let the total OUTPUT be x quintals. and after 14% the NET output is 68,400 quintals. Total output - Net output = Wasted output $= > x - 68400 = 14\% \: of \: total \: output$ $= > x - 68400 = \frac{14}{100} \times x$ $= > x - \frac{14x}{100} = 68400$ $= > \frac{100x - 14x}{100} = 68400$ $= > 86x = 64800 \times 100$ $= > x = \frac{68400 \times 100}{86}$ $= > x = 79534.88 \: quintals$ so, the total output is 79534.88 quintals. B) Number of students who secured first div $= \frac{10}{100} \times 740$ $= 74 \: students$ => Number of students who secured 2nd div, $= \frac{15}{100} \times 740$ $= 111 \: students$ => number of students who just passed $= \frac{10}{100} \times 740$ $= 74 \: students$ So REMAINING students who failed = $740 - (74 + 74 + 111) \\ = 481$ So, percentage of failed students $= \frac{481}{740} \times 100$ $= 65\%$ So, percentage of students failed is 65%