UTS Fenno Steginga Assignment

Name : Fenno Steginga
NIM : 064.06.036
Lecture : Mam Anna Tohir

This is my mid test assignment.


Question,,


A concrete aggregate mix is required to contain at least 31% sand by volume for proper batching. One source of material, which has 25% sand and 75% coarse aggregate, sells for $3 per cubic meter. Another source, which has 40% sand and 60% coarse aggregate, sells for $4.40 per cubic meter. Determine the least cost per cubic meter of blended aggregates.
Answer :
The least cost of blended aggregates will result from maximum use of the lower cost material. The higher cost material will be used to increase the proportion of sand up to the minimum level (31%) specified.
Let x = portion of blended aggregates from $3.00/m cubic source
1 – x = portion of blended aggregates from $4.00/m cubic source
Sand balance :
X(0.25) + (1 – x)(0.40) = 0.31
0.25x + 0.40 – 0.40x = 0.31

X = 0.31 – 0.40 = -0.09
0.25 – 0.40 -0.15
= 0.60
Thus the blended aggregates will contain :
60% of $3.00/m cubic material
40% of $4.40/m cubic material
The least cost per cubic yard of blended aggregates :
= 0.60($3.00) + 0.40($4.40) = 1.80 + 1.76
= $3.56/m cubic