Let the characteristic strength be defined as that value. below which not more than $50 \%$ of the results are expected to fall. Assuming a standard deviation of $4 \mathrm{MPa}$. the target mean strength (in MPa) to be considered in the mix design of a M25 concrete would be

(A) 18.42

(B) 21.00

(C) 25.00

(D) 31.58

Let the characteristic strength be defined as that value. below which not more than $50 \%$ of the results are expected to fall. Assuming a standard deviation of $4 \mathrm{MPa}$. the target mean strength (in MPa) to be considered in the mix design of a M25 concrete would be

(A) 18.42

(B) 21.00

(C) 25.00

(D) 31.58

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