Asolid is built from three identical cylinders, one rectangular prism and one triangular prism. the cylinders have base radii of 2 m and heights of 5 m, the rectangular prism has base side lengths of 4 m and 5 m, and a height of 10 m, and the triangular prism has base height of 4 m, base length of 5 m and height of 20 m. find the volume of the solid in dm2. (take π = 3.14)
24,840 dm2
31,400 dm2
58,840 dm2
78,840 dm2
number 1 is 30% more than number 3 and number 2 is 40% more than number 3. find the ratio of number 1 to number 2.
3: 4
8: 10
13: 14
14: 17
it takes 8 hours for pump a to fill a tank, and 6 hours for pump b to fill the same tank. if pumps a and b are used together with pump c, the tank can be filled in 2 hours. how long would it take pump c to fill the tank on its own?
3 hours
4.2 hours
4.8 hours
5.4 hours
a factory produces fertiliser at the rate of 4,800 kg/hr. one month, the owner decides to increase its production in the ratio 9: 4. 6 months later, the owner decides to decrease the new production rate in the ratio 4: 5. what proportion of the original production rate is the new production rate?
5: 9
4: 5
4: 9
9: 5

increase masses, decrease separation

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.

statement #3 on andre"s list is false.