Question

Gautam takes 5 hours to paint a wall and gambhir takes 6 hour to paint the same wall .if they work together ,how long will they take to paint the wall

Answer 1

let the total work be 30 units.
Gautam's 1 hour work = 30/5 = 6 units
Gambhir's 1 hour work = 30/6 = 5 units
work done by both in 1 hour = 6+5= 11 units
work done = speed × time
30= 11× t
t=30/11=2 8/11 hour
t = 2 hours 43 minutes 33 seconds

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Answer 2

Gautam's 5 hours work=1 unit,

Gautam's 1 hour work =1/5 unit,

Gambhir's 6 hours work=1 unit,

Gambhir's 1 hours work=1/6 unit,

then
Gautam and Gambhir 1 day work together=1/5 +1/6 =(6+5)/30,

Gautam and Gambhir 1 day work together=11/30 units,

Gautam and Gambhir 30 days work =11 units,

therefore

Gautam and Gambhir does complete work =30/11 days