Bank Exam Time & Work Master – Page 5 (Big Set)
Shortcut Formulas • LCM Method • Step-by-Step Solutions
🔷 Core Formula
If A = a days, B = b days
Together = (a × b) / (a + b)
Work = Rate × Time
🔷 LCM Method (Topper Trick)
Take total work = LCM of days
Example:
A = 6 days → Work = 1/6
B = 12 days → Work = 1/12
Total = 1/6 + 1/12 = 3/12 = 1/4
Time = 4 days
🔷 Solved Problems
Q1. A=6, B=12
= (6×12)/(6+12)
= 72/18 = 4 days
Q2. A=8, B=8
= 64/16 = 4 days
Q3. A=4, B=6
= 24/10 = 2.4 days
Q4. A=5, B=10
= 50/15 = 3.33 days
Q5. A=3, B=6
= 18/9 = 2 days
Q6. A=12, B=18
= 216/30 = 7.2 days
Q7. A=15, B=10
= 150/25 = 6 days
Q8. A=20, B=30
= 600/50 = 12 days
Q9. A=9, B=18
= 162/27 = 6 days
Q10. A=7, B=14
= 98/21 = 4.66 days
🔷 Three Persons Shortcut
T = abc / (ab + bc + ca)
Q11. A=4, B=6, C=12
= 288 / (24+72+48)
= 288/144 = 2 days
Q12. A=3, B=4, C=6
= 72 / (12+24+18)
= 72/54 = 1.33 days
Q13. A=2, B=3, C=6
= 36 / (6+18+12)
= 36/36 = 1 day
🔷 Efficiency Concept
If A is twice as fast as B:
A : B = 2 : 1
Q14. A=10 days, B slower
B = 20 days
Q15. A:B = 3:2, total work=60
A = 36, B = 24
🔥 Topper Tricks
- Use LCM method for speed
- Convert to ratio
- Avoid fractions if possible
- Use efficiency concept
Final Tip
Work = Efficiency × Time → Think in reverse
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