Job Solution | NRBC BANK LTD.

NRBC Bank Ltd. || TJO (15-01-2021) || 2021

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গণিত

One pump drains one-half of a pond in 3 hours, and then a second pump starts draining the pond. The two pumps working together finish emptying the pond in one and half hour. How long would it take the second pump to drain the pond if it had to do the job alone?

$H e r e, 1 h o u r = 60 m i n u t e s .$

$∴ 24 h o u r = 24 x 60 = 1440 m i n u t e s .$

$T h e D o l p h i n c o m e s u p a i r i n 1440 m i n u t e s = \frac{1440}{2} = 720 t i m e s$

$& T h e W h a l e c o m e s u p a i r i n 1440 m i n u t e s = \frac{1440}{5} = 288 t i m e s .$

$∴ R e q u i r e d p e r c e n t a g e = (\frac{720 - 288}{288} \times 100) = (\frac{432}{288} \times 100) % = 150 %$

On average, the bottle-nosed dolphin comes up for air once every two minutes; the beluga whale, close relative, comes up for air on average once every five minutes. The number of times a bottle-dolphin would come up for air in a 24 hour period is approximately what percent greater than number of times a beluga whale would come up for air in that same period?

$T h e f i r s t p u m p c a n d r a i n i n 3 h o u r s \frac{1}{2} o f t h e p o n d$

$∴ T h e f i r s t p u m p c a n d r a i n i n 1 h o u r s = \frac{1}{2 \times 3} = \frac{1}{6} o f t h e p o n d$

$B o t h p u m p s c a n d r a i n i n 1 \frac{1}{2} o r \frac{3}{2} h o u r s = 1 - \frac{1}{2} = \frac{1}{2} o f t h e p o n d .$

$∴ B o t h p u m p s c a n d r a i n i n 1 h o u r s = \frac{1}{2} \times \frac{1}{3} = \frac{1}{3} o f t h e p o n d .$

$∴ W o r k i n g a l o n e t h e s e c o n d p u m p c a n d r a i n i n 1 h o u r = \frac{1}{3} - \frac{1}{6} = \frac{2 - 1}{6} = \frac{1}{6} p a r t o f t h e p o n d$

$∴ T h e s e c o n d p u m p s c a n e m p t y \frac{1}{6} o f t h e p o n d i n 1 h o u r$

$∴ T h e s e c o n d p u m p c a n e m p t y 1 o r f u l l p o n d n = \frac{6 \times 1}{1} = 6 h o u r s .$

Job Solution | NRBC BANK LTD.

NRBC Bank Ltd. || TJO (15-01-2021) || 2021

All

গণিত

One pump drains one-half of a pond in 3 hours, and then a second pump starts draining the pond. The two pumps working together finish emptying the pond in one and half hour. How long would it take the second pump to drain the pond if it had to do the job alone?

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