13 p.s.i.
1 kg/sq cm = 14.2233 psi 140 kg.sq cm = 140 x 14.2233 psi = 1991.262 psi
That would be to deflate it.
psi is a pressure and pound is a mass or weight. That is like apples and bananas. EDIT: I think the question refers to a basketball. For example, on my basketball it reads: "Inflate 7 to 9 LBS". This is very confusing indeed, with no mention of pressure. However, they actually mean, in this case, "LBS per square inch" - I don't know why it's not specified, but POUNDS in this case means POUNDS PER SQUARE INCH. Hooray for strange ways of specifying pressure!
There is no mathematical conversion needed - 1 psi is equal to 1 psi. The terms "psig" and "psi" are often used interchangeably to refer to pounds per square inch of pressure. However, "psig" specifically denotes pressure relative to the local atmospheric pressure, while "psi" is an absolute measure.
To convert 14.73 psi to 15.025 psi, you need to increase the pressure by the difference between the two values. Subtract 14.73 from 15.025, which gives you 0.295 psi. Therefore, you can achieve the conversion by adding 0.295 psi to 14.73 psi, resulting in 15.025 psi.