Sunday
May 26, 2013

# Posts by HARISH

Total # Posts: 21

maths
for a particular stretch of road it is estimated that on average one car in ten exceeds the speed limit. on a particular day 2003 cars use that stretch of road. use a suitable approximation to find t

chemistry
Plastic articles can be chromium-plated by coating them with thin layer of graphite paste,placing them in a bath of aqueous chromium(III) sulphate and electroplating. a)Suggest a reason why the article is first coated with graphite. b)what substance could be used for the other...

maths
The lifetime in hours of a certain make of batteries follows a normal distribution with mean 160 and standard deviation 30. Calculate the interval, symmetrical about the mean within which 75% of the battery lifetimes lie.

maths
the masses of lettuces sold at a market stall are normally distributed with the mean 600g and standard deviation 20g. 1) find the mass exceeded by 10% of the lettuces. 2) 5% of the lettuces have a mass less than M g. find M

maths
x ~ N(400,64) 1) Find the limits within which the central 95% of the distribution lies. 2) find the interquartile range of the distribution.

maths
the heights of female students at a particular college are normally distributed with the mean 169 cm and standard deviation 9 cm. 1) Given that 80% of these female students have a height less than h cm ,find the value of h. 2) Given that 60% of these female students have a hei...

maths
An intelligence test used in a particular country has scores which are normally distributed with mean 100 and standard deviation 15.In a randomly selected group of 500 people sitting the test, estimate how many have a score 1)higher than 140, 2)below 120, 3)between 100 and 110...

chemistry
in an attempt to establish the formula of an oxide of nitrogen , a known volume of the pure gas was mixed with hydrogen and passed over a catalyst at a suitable temperature. 100% conversion of the oxide to ammonia and water was shown to have taken place. NxHy gives xNH3 + YH20...

physics
A student wishes to measure the resistivity of glass. A teacher suggests that its resistivity is of the order of 10^6 Ω m which is very large. Resistivity ρ is defined by the equation: ρ = RA / l where R is resistance, A is cross-sectional area and l is the leng...

chemistry
an aqueous solution contains 1 mol of S2O3 ions and this reduces 4 mol chlorine molecules.What is the sulphur containing product of this reaction?

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