16 men can do a work in 5 days 12 women can do it
in 8 days while 20 boys can finish it in 6 days. 5
men, 6 women and 10 boys started work together
but after 3 days men and women left how many more
boys are needed to finish remaining workin 3/4 of a
day
16 पुरुष किसी कार्य को दिनों में, 12 महिलाएं उसी कार्य को 8 दिनों
में, जबकि लड़के इसे 6 दिनों में कर सकते हैं। 5 पुरुष, 6 महिलाए
और 10 लड़को ने एक साथ कार्य करना शुरू किया लेकिन 3 दिनो के
बाद पुरुषों और महिलाओं ने कार्य छोड़ दिया। तो ज्ञात करे कि 3/4 दिन
में शेष कार्य पूरा करने के लिए कितने और लड़को की आवश्यकता
होगी?
Answers
You will often be able to ballpark or find the exact solution by just working on the multiples of the given equations.
Say rate of work of each man is M and that of each woman is W.
Given: 12M + 16W = 1/5 (Combined rate done per day)
______3M + 4W = 1/20 (in lowest terms) ...........(I)
Given: 13M + 24W = 1/4 ......................................(II)
Reqd: 7M + 10W = ?
Using equations (I) and (II) we need to find the sum of 7M and 10W. We can get a multiple of 7M in various ways:
(3M + 4W = 1/20) * 5 gives 15M + 20W = 1/4
Adding this to equation II, we get 28M + 44W = 1/2
7M + 11W = 1/8
7 men and 11 women complete the work in 8 days. 7 men and 10 women will take a little more than 8 days to complete the work. If you do get such a question in GMAT, you will easily be able to manipulate the equations to get the desired equation. Finding the values of M and W is way too painful to interest GMAT.