Question 537043
The ratio of cement to sand = 4/5

multiply by a common factor x
4x parts of cement 
5x parts of sand.

4x+5x=144
9x=144
x=144/9
x=16

4x/5x = 4*16/5*16= 64/80

cement = 64 kg
Sand = 80 kg
CHECK

64+80 = 144

64/80 = 4/5

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