+16 Mr. Butler is filling planter boxes with soil. He has soil that is 30% sand, and he buys 9 pounds of a commercial potting soil that is 18% sand. He mixes some of his soil with the 9 pounds of commercial potting soil. The resulting soil mixture is 21% sand. How many pounds of his soil did Mr. Butler use?
+36916 Soil sand content = x * 30% = .3x
Commercial soil sand content = 9 x 18% = 1.62 pounds
resulting mixture is (x+9) * 21%
added together must equal what is put in
.3x + 1.62 = .21 (x+9)
.3x + 1.62 = .21x + 1.89
.09x = .27
x= 3 pounds
Let the amount of Mr. Butler's 30% sand =S
0.30S + 0.18(9) =0.21(9+S)
0.30S + 1.62 =1.89 + 0.21S
0.30S - 0.21S =1.89 - 1.62
0.09S =0.27
S =0.27 / 0.09
S = 3 pounds - of 30% sand that Mr. Butler used.
+16 That's what we had.... I should really start learning to trust my gut. Thank you so much for your expedient reply
+36916 Soil sand content = x * 30% = .3x
Commercial soil sand content = 9 x 18% = 1.62 pounds
resulting mixture is (x+9) * 21%
added together must equal what is put in
.3x + 1.62 = .21 (x+9)
.3x + 1.62 = .21x + 1.89
.09x = .27
x= 3 pounds
