A alone can do a work of Tk. 1200 in 6 days. By engaging an assistant, the work is completed in just 4 days. The share the assistant would receive is -

Question: A alone can do a work of Tk. 1200 in 6 days. By engaging an assistant, the work is completed in just 4 days. The share the assistant would receive is -

Solution:
A alone can do the work in 6 days
in 1 day,
A can do 1/6
both can do 1/4
the assistant can do (1/4) - (1/6)
= (3 - 2)/12
= 1/12

So
A : Assistant = 1/6 : 1/12 = 2 : 1

Hence, the share of the assistant is (1200 × 1/3)
= 400 Tk.