OG 12th Problem Solving 121-140

Question 121 – “There are 8 teams in a certain league and each team…”

OG Explanation is fine. Alternatively, you could do it like problem #116 and sum 1 + 2 + … + 7.
Khan Academy Link OG 11th 121 – 1:40

Question 122 – “An operation θ is defined…”
OG Explanation is fine.
Khan Academy Link OG 11th #122 – Begins at 4:30

Question 123 – “The price of lunch for 15 people…”
OG Explanation is fine.
Khan Academy Link OG 11th #123 – Begins at  6:35

Question 124 – “In Town X, 64 percent of the….”
OG Explanation is fine.

Question 125 – “If p/q < 1, and p and q….” OG Explanation is fine.
Khan Academy Link OG 11th #125 – Begins at 1:45

Question 126 – “It would take one machine 4 hours…” OG Explanation is fine. Khan Academy Link OG 11th #126, 3.05 Question 127 – “To mail a package….” OG Explanation is okay. Since the first pound costs more than the additional pounds( from x > y ), a combined package is definitely cheaper. I think the easiest ways is to pick numbers. Suppose it costs 10 cents for the first pound and 2 cents for the second pound. To ship separately, the 3 pound package will cost 14 cents and the 5 pound package will cost 18 cents. Total, this is 32 cents. If we combine the packages, the total cost will be 10 cents for the first pound and 14 cents for the additional 7 pounds. The result is 24 cents. We save 8 cents.
Choice A: savings x-y = 10 – 2 = 8 cents CORRECT
Choice B: Savings y-x = 2 – 10 = negative savings = INCORRECT
Choice C: Savings = x = 10 cents INCORRECT
We already decided that combined was cheaper, so we don’t need to check D and E.
Khan Academy Link OG 11th #127, 5:25

Question 128 – “If money is invested at r percent…”
OG Explanation is fine.
Khan Academy Link OG 11th #128 – 8:30

Question 129 – “On a recent trip…”
OG Explanation is fine. Note: 11th Edition question has slightly different answer choices but the question is the same.
Khan Academy Link OG 11th #129 – Begins at 0:00

Question 130 – “Which of the following inequalities…”
OG Explanation is not very clear.

Sal Khan better explains the OG method.
Khan Academy Link OG 11th #130 at 3:45

Question 131 – “A factory has 500 workers….”
OG Explanation is fine.
Khan Academy Link OG 11th #131 – Begins at 6.40

Question 132 – “In a small snack shop…”
OG Explanation is fine. Alternatively, the average daily revenue is $400 per day and the first 6 days, they are $40 short. In total, they are $240 short by the end of the 6th day. The next 4 days, they need to make up a total of $240 or $60 per day on average. The shop must make $400 + $60 in revenue for the next 4 days.
Khan Academy Link – 132, 9.05

Question 133 – “A certain country had a total annual…”
OG Explanation is fine.
Khan Link OG 11th Edition #133, – Begins at 0:00

Question 134 – “A certain rectangular window is twice as long…”
OG Explanation is fine.
Khan OG 11th Question 134, begins at 1:50

Question 135 – “The diagram above…”
OG Explanation is fine.
Khan Academy Link #135, begins at 3:10

Question 136 – “If the operation _ is defined by….”
OG Explanation is fine.
Khan Academy Link #136, begins at 5:45

Question 137 – “A bar over a sequence…”
OG Explanation is fine.
Khan Academy Link – Begins at 8:15

Question 138 – “At a loading dock….
OG Explanation is fine. Alternatively, we could pick numbers. The night crew has 4/5 as many workers as the day crew so let’s say the night crew has 4 people and the day crew has 5. If the night crew loaded ¾ as many boxes, let’s say the night crew loaded 3 boxes and the day crew loaded 4 boxes. The total boxes loaded is 4 x 3 = 12 by night crew and 5 x 4 =20 by the day crew. So the day crew loaded 20/32 or 5/8 all the boxes.
Khan Link #138 – Begins at 0:00


Question 139 – “A restaurant meal cost $35.50…”
OG Explanation is fine.
Khan Link #139 - Begins at 2:50

Question 140 – “In a weight-lifting competition…”
OG Explanation is fine. Alternatively, you can go directly to the answer choices and plug and chug.
Khan 140 – 5:25



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