For this case we can propose an equation that will allow us to find the price of one of the books knowing the price of the other.
x: Let the variable that represents the price of the book with a green sticker
y: Let the variable that represents the price of the book with a yellow sticker
According to the statement we have:


Finally, we can substitute the price of one of the books and clear the value of the other as the case may be.
Answer:

Answer:
AAS(Angle-Angle-Side) postulate states that if two angles and the non-included side one triangle are congruent to two angles and the non-included side of another triangle, then the two triangles are congruent
In triangle RAS and triangle QAT
[Angle]
[Side] [Given]
By Base Angle Theorem states that in an isosceles triangle(i.e, AST), the angles opposite the congruent sides(AS =AT) are congruent.
⇒
[By base ∠'s of isosceles triangle are equal]
By definition of supplementary angles, if two Angles are Supplementary when they add up to 180 degrees.
,
are supplementary and
,
are supplementary.
⇒
and
Two
supplementary to equal 
Since,
then, we get;
[Angle]
then, by AAS postulates,

By CPCT[Corresponding Part of Congruent Triangles are equal]
Hence Proved!
Answer:
9.09
Step-by-step explanation:
x=speed of boat
y=speed of water current
Downstream relative speed = x+y
Upstream relative speed = x-y
Distance remains the same for both upstream and downstream.
a) Distance travelled downstream = speed x time = 3(x+y)
Distance travelled upstream = speed x time = 3.6(x-y)
b) Since both distances are equal, we can write
3(x+y)= 3.6(x-y)
3x+3y = 3.6x-3.6y
6.6y = 0,6x
x=11y: y=x/11
c) Water current has speed as 1/11 times of that of boat
In percent this equals 100/11 = 9.09%
11/7
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