Determine the cement content of the concrete (air entrained) and the oven-dry weight of the coarse aggregate according t

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Determine the cement content of the concrete (air entrained) and the oven-dry weight of the coarse
aggregate according to the following condition:
Required design strength = 27.6 MPa; standard deviation of concrete (more than 30 samples) = 2.1 MPa;
water content = 141 kg/m3; oven-dry density of the coarse aggregate (19 mm nominal maximum size) =
1761 kg/m3; fineness modulus = 2.4; and minimum cement for 19 mm aggregate = 320 kg/m3