Answer:
5 bags of cement are required.
Step-by-step explanation:
Since to make concrete, the ratio of cement to sand is 1: 3, if cement and sand are sold in bags of equal mass, to determine how many bags of cement are required to make concrete using 15 bags of sand the following calculation must be done:
Cement = 1
Sand = 3
3 = 15
1 = X
15/3 = X
5 = X
Therefore, 5 bags of cement are required.
1.
2 yellow marables of 10 all marables
2.
1 yellow marable of 9 all marables
(5/15)(4/14) = 4/42 = 2/21
FG = 7
5x+2+3x-1=9
8x+1=9
8x = 8
x = 1
FG = 5(1)+2 = 7