Triangles QST and RST are similar. Therefore, the following is true:
q s
--- = ---- This results in 10q=rs.
r 10
Also, since RST is a right triangle, 4^2 + s^2 = q^2.
Since QST is also a right triangle, s^2 + 10^2 = r^2.
4 s
Also: ---- = ----- which leads to s^2 = 40
s 10
Because of this, 4^2 + s^2 = q^2 becomes 16 + 40 = 56 = q^2
Then q = sqrt(56) = sqrt(4)*sqrt(14) = 2*sqrt(14) (answer)
ωєℓℓ αℓℓ уσυ нανє тσ ∂σ ιѕ ∂ινι∂є 1,568 ву 28
ωнι¢н ωιℓℓ єqυαℓ тнє ωαℓℓ тσ вє 56 fєєт.
ι нσρє ι ¢συℓ∂ нєℓρ уσυ
Let x be the number of pounds of the $1.35 beans. The cost of those beans is $1.35 * x, or 1.35x.
<span>Let y be the number of pounds of the $1.05 beans. The cost of those beans is $1.05 * y, or 1.05y. </span>
<span>We know that 120 pounds of the mix sells for $1.15/pound, for a total of 120 * 1.15 = $138. </span>
<span>x + y = 120 </span>
<span>1.35(x) + (1.05)y = 138 </span>
<span>We can rewrite the first as </span>
<span>x = -y + 120 </span>
<span>Now we can substitute (-y + 120) in for (x) in the second equation, because we just proved they're equal. </span>
<span>1.35(x) + 1.05(y) = 138 </span>
<span>1.35(-y + 120) + 1.05y = 138 </span>
<span>-1.35y + 162 + 1.05y = 138 </span>
<span>-0.3y + 162 = 138 </span>
<span>-0.3y = -24 </span>
<span>y = 80 </span>
<span>And since x + y = 120, that means x = 40. </span>
<span>Check: </span>
<span>40 pounds of x at $1.35 costs 40 * 1.35, or $54. </span>
<span>80 pounds of y at $1.05 costs 80 * 1.05, or $84. </span>
<span>Do those add up to our target total, according to the question, of 120 * 1.15 = $138? </span>
