Answer:
12,000psi
Step-by-step explanation:
Given the 7 days strength of a concrete to be 3000psi, to calculate the estimated mean28-day strength of this concrete the following equality equation is applied
7 days strength = 3000psi
28days strength = y
To get y, we will Cross multiply
7 × y = 28×3000
7y = 28×3000
7y = 84000
Divide both sides by 7
7y/7 = 84000/7
y = 12000
hence the estimated mean 28-day strength of this concrete is 12,000psi
