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Let’s assume the total work is 360 units. Pankaj alone can do the same piece of work in 45 days. Efficiency of Pankaj = 360/45 = 8 units/day The efficiency of Rahul is 12.5% more than the efficiency of Pankaj. Efficiency of Rahul = (100+12.5)% of 8 = 112.5% of 8 = (112.5x8)/100 = 9 units/day Rahul alone can do 60% of the same piece of work in (z-4) days. Time taken by Rahul alone to complete the work alone = [(z-4)/60]x100 = [(z-4)/3]x5 So [[(z-4)/3]x5]x9 = 360 [(z-4)/3]x5 = 40 [(z-4)/3] = 8 (z-4) = 24 z = 24+4 z = 28 Queen and Rahul together can do 75% of the same piece of work in (0.5z+4) days. Time taken by Queen and Rahul together to complete the whole work = [(0.5z+4)/75]x100 = [(0.5z+4)/3]x4 (Efficiency of Queen + 9)x[(0.5z+4)/3]x4 = 360 Put the value of ‘z’ in the above equation. (Efficiency of Queen + 9)x[(0.5x28+4)/3]x4 = 360 (Efficiency of Queen + 9)x[(14+4)/3]x4 = 360 (Efficiency of Queen + 9)x[18/3]x4 = 360 (Efficiency of Queen + 9)x6x4 = 360 (Efficiency of Queen + 9)x24 = 360 (Efficiency of Queen + 9) = 15 Efficiency of Queen = 15-9 = 6 If the efficiency of Queen is ‘y’% less than that of Pankaj. 6 = (100-y)% of 8 6 = [(100-y) x 8]/100 3 = [(100-y) x 4]/100 300 = (400-4y) 4y = 400-300 4y = 100 y = 25 Required percentage = (z/y)x100 = (28/25)x100 = 28x4 = 112%
In a circle, the length of a chord AB is 48 cm & radius is 25 cm. Find the distance between centre and chord.
Two chords AB and CD of a circle intersect at E such that AE = 3.4 cm, BE = 4.2 cm and CE = 2.6 cm. What is the approximate length of DE?
The minute hand of a clock is 28cm long. Find the area on the face of the clock swept by the minute hand between 8 a.m. and 8: 45a.m
One chord of a circle is given as 18.5 cm. Then the radius (r) of the circle must be:
The wheel of a car made 300 rotations. How much distance did the car travel if the diameter of the wheel is 28 inches? (1 inch = 2.54cm)