Question

Example 24
20 days before B goe
s away. In how many days will A manage to finish the remaining work?
A can do a piece of work in 80 days and B in 100 days. They work together for first​

Answer 1

Answer:

Let A and B work for 20- days and then A- alone completes the work in N- days, then

(20+N)/80 + 20/100 = 1

So 5(20+N)+ 4(20) = 400

So 5N= (400- 180)= 220

So N= 220/5= 44- days

. Therefore A will finish the remaining unfinished work in 44- days.

========================== Another Simple Method:

Part of the work completed in 20- days

= 20/80+ 20/100= 1/4+ 1/5

= 9/20- part of the work.

Therefore the remaining 11/20- part of the work will be completed by A in = (11/20)÷ (1/80)= 11/20 x 80= 44- days. Ok.

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