Concrete is made by mixing screenings cement and sand in the ratio 3:1:15. How much sand would be needed to make 125 tons of concrete?

=    98.7 tons

Step-by-step explanation:

ratio =   3:1:15

amount of sand needed =    (15/19)*125      /  3 + 1 +15  =19

hello from mrbilldoesmath!

answer:   x (x+6)^2, choice b

discussion:

factor x out of the equation:

x^3 + 12x^2 + 36x = x (x^2 + 12x + 36).

note that 6+6 = 12 and 6*6 = 36 so the above factors into:

x (x+6)^2

which is choice b

you,

mrb