Question 231691
The direct way to solve this problem is to add the three ratios:
1+3+4=8 
Now find how many sets of 8 there are in the total of 1,000.
1,000/8=125 for each 1 of the elements in the ratio.
1*125=125 pds. of cement.
3*125=375 pds. of sand.
4*125=500 pds. of gravel.
Proof:
125+375+500=1,000
1,000=1,000