Answer: B) 6 kmph Explanation: Speed of the stream = 1Motor boat speed in still water be = x kmphDown Stream = x + 1 kmphUp Stream = x - 1 kmph[35/(x + 1)] + [35/(x - 1)] = 12x = 6 kmph

Answer: C) 2/21 Explanation: Given that there are three blue marbles, four red marbles, six green marbles and two yellow marbles.   Probability that both marbles are blue = ³C₂/¹⁵C₂ = (3 x 2)/(15 x 14) = 1/35 Probability that both are yellow = ²C₂/¹⁵C₂ = (2 x 1)/(15 x 14) = 1/105 Probability that one blue and other is yellow = (³C₁ x ²C₁)/¹⁵C₂ = (2 x 3 x 2)/(15 x 14) = 2/35   Required probability = 1/35 + 1/105 + 2/35 = 3/35 + 1/105 = 1/35(3 + 1/3) = 10/(3 x 35) = 2/21

Answer: A) 26 July Explanation:

Answer: A) 9 Explanation: Speed in still water = Average of Speed in Upstream and speed in Downstream = 1/2 (12 + 6) kmph = 9 kmph.

Answer: D) 2 hrs Explanation: Speed in downstream = 96/8 = 12 kmph Speed of current = 4 km/hr Speed of the boatman in still water = 12 – 4 = 8 kmph Speed in upstream = 8 – 4 = 4 kmph Time taken to cover 8 km upstream = 8/4 = 2 hours.

Answer: D) 20 years Explanation: Present total age of the members = 26(5) = 130 years.   Present age of the youngest member = 10 years   Present total age of the remaining four members = 130 -10 = 120 years   Their average age at the time of the birth of the youngest member = 120-4×104 = 30 - 10 = 20 years.

Answer: C) ओवर हैट स्पष्टीकरण: कंप्यूटर पर स्लॉट कवर कंप्यूटर के अंदर जमा धूल को कम करता है। इसलिए स्लॉट कवर उचित स्थान पर मौजूद होना चाहिए। लापता कवर केस के एयरफ्लो डिज़ाइन को बाधित कर सकते हैं और ओवरहीटिंग की समस्या पैदा कर सकते हैं।

Answer: C) Larva Explanation: A Bill becomes a Law; a Larva becomes an insect. (Or) A Bill turns into a law; a Larva turns into an Insect.