Paper 1 · Mathematical Reasoning and Aptitude
UGC NET December 2023 (12.12.2023) Shift-II
A can do one-third of a work in 4 days and B can do three-fourth of the work in 15 days. Together, they will complete the work in:
A4 and one-fourth days
B5 and three-fourth days
C8 and one-fourth days
D7 and one-half days ✓ Correct
Correct answer: (D) 7 and one-half days — Together A and B complete the work in 7 and one-half days, so that is the answer.
Explanation
★Together A and B complete the work in 7 and one-half days, so that is the answer.
★A does one-third of the work in 4 days, so A does the whole work in 12 days.
★B does three-fourths of the work in 15 days, so B does the whole work in 20 days.
★In one day A does 1 over 12 and B does 1 over 20 of the work.
★Together they do 1 over 12 plus 1 over 20, which is 8 over 60, that is 2 over 15 per day.
★So the time taken together is 15 over 2, which is 7 and one-half days.
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