<h3>Jason bought 20 stamps of $0.41 each and 8 postcards of $0.26 each.</h3>
<em><u>Solution:</u></em>
Let stamps be s and postcards be p
Given that,
The number of stamps was 4 more than twice the number of postcards
s = 4 + 2p -------- eqn 1
Jason bought both 41-cent stamps and 26-cent postcards and spent $10.28
41 cent = $ 0.41
26 cent = $ 0.26
Therefore,
0.41s + 0.26p = 10.28 --------- eqn 2
Substitute eqn 1 in eqn 2
0.41(4 + 2p) + 0.26p = 10.28
1.64 + 0.82p + 0.26p = 10.28
1.08p = 10.28 - 1.64
1.08p = 8.64
Divide both sides by 1.08
p = 8
Substitute p = 8 in eqn 1
s = 4 + 2(8)
s = 4 + 16
s = 20
Thus Jason bought 20 stamps and 8 post cards
By moving the signs he actually changed the number itself. He changed -6 from a negative to a positive and 5 from a positive to a negative. Both equations give different answers.
Hopefully this helps :)
B. triangle ABC is isosceles. The angles add up 180 degrees.
First, sum up the total expenses for the original plan
Duque de Caxias + Campinas + Rio de Janeiro + Guarulhos = 242+185+193+120 = R$740
It is clearly over the intended budget. The average cost per itinerary is around R$200 so we will consider making a swap on either Duque de Caxias and Rio de Janeiro. Possible answers are (b) or (c)
for (b) Replace Duque de Caxias with Fortaleza, we will have
Fortaleza + Campinas + Rio de Janeiro + Guarulhos =
⇒ 201+185+193+120 = R$699 ⇒ This is exactly the budget intended for the trip
for (C) Replace Rio de Janeiro with Porto Alegre
Duque de Caxias + Campinas + Porto Alegre + Guarulhos =
⇒ 242 + 185 + 153 +120 = R$ 700 ⇒ This is over R$1
The answer is (b)
