Question

Two man undertook to do a job for Rs.$1400$. One of them can do it alone in $7$ days and the other in $8$ days. With the assistance of a boy, they together completed the work in $3$ days. How much money did the boy get ?

• A. Rs. $265$
• B. Rs. $275$
• C. Rs. $285$
• D. Rs. $295$

Answer 1

Answer: (B)

Rs. $275$

Let $A$ can do a piece of work in a $7$ days and $B$ in $8$ days and together they are paid is Rs.$1400$.

Let the boy he $C$.

$A$'s one day work$=\frac{1}{7}$ $B$'s one day work$=\frac{1}{8}$

$A$'s $3$ days work$=\frac{3}{7}$ $B$'s $3$ days work$=\frac{3}{8}$

$\therefore C$'s work $1-\frac{3}{7}-\frac{3}{8}=\frac{56-24-21}{56}=\frac{11}{56}$

$C$'s work money in $3$ days$=\frac{11}{56}\times$ Rs $1400$

=Rs $275$