P completes work in 24 days, Q in 9 days, R in 12 days. Time taken together is ____. A. 10 B. 9 C. 11 D. 12 Explanation: Sum of rates gives time = 10 days.
P and Q complete work in 8 days, Q and R in 12 days. Time for all three is ____. A. 7 B. 8 C. 9 D. 10 Explanation: Combined work rate leads to 8 days.
P, Q, and R complete work in 30, 24, and 20 days. Total work done in 10 days is ____. A. 10 B. 8 C. 18 D. 19 Explanation: Combined work = 10 × (sum of rates).
P and Q complete work in 20 and 12 days. Time together is ____. A. 5 days B. 10 days C. 15 days D. 12 days Explanation: The combined rate gives 10 days.
P and Q complete work in 15 and 10 days. Together they complete in ____. A. 6 B. 12 C. 22 D. 20 Explanation: Combined rate = 1/15 + 1/10 = 1/6 → time = 6 days.
From first 20 natural numbers, probability of selecting even number is ____. A. 1/2 B. 16/19 C. 4/5 D. 17/20 Explanation: 10 even numbers → 10/20 = 1/2.
Out of the earnings of Rs. 720, a person spends 65%. Savings are ____. A. Rs. 350 B. Rs. 390 C. Rs. 252 D. Rs. 316 Explanation: Savings = 35% of 720 = 252.
Out of 15 consecutive numbers, probability of selecting two odds is ____. A. 10/17 B. 10/19 C. 46/105 D. Cannot be determined Explanation: Exact distribution unclear without the count of odds.
Out of 100 students, 50 failed English, and 30 failed Math. If 12 failed both, how many failed at least one? A. 26 B. 28 C. 32 D. 68 Explanation: Total = 50 + 30 − 12 = 68.
Out of 10 persons, 4 are graduates. Probability that at least one is graduate when 3 are chosen is ____. A. 1/6 B. 5/8 C. 3/8 D. 5/6 Explanation: Use the complement method → 1 − (6C3/10C3).