B द्वारा लिए गए समय के `(3)/(4)` समय में a उसका आधा काम करता है यदि दोनों मिलकर 18 दिनों में काम ख़त्म करते है तो B अकेले काम को कितने दिनों में ख़त्म कटेगा ?

Options

A. 30days
B. 35 days
C. 40 days
D. 45 days

Answer

a

Explanation

`{:((a),A,:,B),(time ,3,:,4),(eff,1,:,2) ,("we have" ," to do "," time equal so",),(,A,:,B),(time,3_(xx4),:,4_(xx3)),(eff,1_(xx4),:,2_(xx3)),(,A,:,B),(time ,12,:,12),(eff,4,:,6):}`
both so the work in 18 days so , total work `=(A+B)'s effxx18=(4+6)xx18=18=180` units B will complete the work in
`(180)/(6) =30` days
alternate
A takes `(3)/(4)th` time of B
`A=Bxx(3)/(4)`
`(A)/(B) =(3)/(4)[time]`
A does half as much work as B
`(A)/(B)=(1)/(2){work]`
we know ,
`(m_(1)h_(1)d(1))/(w_(1))=(m_(2)h_(2)d_(2))/(w_(2)`
`Axx3)/(1)=(bxx4)/(2)`
`(A)/(B)=(2 to "efficiency of A")/(3 to "Efficinecy of B")`
(A+B) 's one days work =(3+2) =5 units
Total work `=5xx18=90`units
time taken by B `=("total wprk") /("eff. of b")`
`=(90)/(3) = 30` days