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1.Time and work: If A can do a piece of work in n days, then A’s 1 day’s work = 1/n 2.   Days from Work:If A’s 1 day’s work = 1/n then A can finish the work in n days  3. Ratio:If A is thrice as good a workman as B, then:Ratio of work done by A and B […]

Introduction : Pipes and cisterns SAMPLE PROBLEMS 1. A tank is filled in 5 hours by three pipes A, B and C. The pipe C is twice as fast as B and B is twice as fast as A. How much time will pipe A alone take to fill the tank? a. 20 hoursb. 25 […]

Subject Overview Why the Psychometric test was included in the Merchant Navy? When you are flying a Plane or you are fighting a war, you need to make decisions in a split of seconds. . Most importantly, at your decisions rest lives of people. In Shipping, with advancement in technology, you have RADARS installed in […]

Introduction: Workshop technology Types of hammers- Types of chisels- Types of screw drivers- Types of files- Types of punches- Bench vice- these are work holding devices which are mounted onto the tops of work benches. They are used to hold work pieces whilst carrying out operations like filling, sawing, bending etc. Hacksaws- these are used […]

Introduction : Time, speed and distance 1 km/hr to m/sec conversion: 2. relative speed of a moving body with the speed x km/h in relation to the other moving body with speed of y km/h:(a)in same direction is the difference of their speed (x-y) km/h.(b) in opposite direction  is the sum of their speed (x+y) […]

1. The mean of the first 10 multiples of 6 is (a) 3.3(b) 33(c) 34(d) none of these 2. In the given data if n = 230, I = 40, cf = 76, h = 10, f = 65, then its median is (a)40(b)46(c)47(d)48 3. For the following frequency distribution: Class Frequency 0 – 5 […]

Introduction: Trigonometry Trigonometry ratios- For the right ΔABC, right-angled at ∠B, the trigonometric ratios of the ∠A are as follows: sin A=opposite side/hypotenuse=BC/AC cos A=adjacent side/hypotenuse=AB/AC tan A=opposite side/adjacent side=BC/AB cosec A=hypotenuse/opposite side=AC/BC sec A=hypotenuse/adjacent side=AC/AB cot A=adjacent side/opposite side=AB/BC Relation between the trigonometry ratios- cosec θ =1/sin θsec θ = 1/cos θtan θ = sin θ/cos θcot θ = cos θ/sin θ=1/tan […]

Centripetal force For instance, A sound wave is characterized by three factors: 1.Amplitude2.Frequency3.Speed Waves A wave is a disturbance in a medium which moves from one point to another and carries energy without a net movement of particles. It may take the form of elastic deformation or a variation of pressure. Mechanical waves A wave that […]

A.1     B.2      C.3     D.4    A.1     B.2      C.3     D.4  A.1     B.2      C.3     D.4  A.1     B.2      C.3     D.4 A.1     B.2      C.3     D.4