The strength of a sample of fully matured concrete is found to be 40 MPa. Find the strength of identical concrete at the age of 7 days, when cured at an average temperature of 20° C during daytime and average temperature of 10° C during night time (take A = 32, B = 54).
1
17.28 MPa
2
26.63 MPa
3
29.23 Mpa
4
22.56 MPa