Maths Olympiad Prep

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Algebra Difficulty 5.1 AIME, harder Find the answer

Round 1

p1. A \100TVhasitspriceincreasedby TV has its price increased by 10\%.Thenewpriceisthendecreasedby. The new price is then decreased by 10\%$. What is the current price of the TV?

p2. If 9w+8x+7y=429w + 8x + 7y = 42 and w+2x+3y=8w + 2x + 3y = 8, then what is the value of 100w+101x+102y100w + 101x + 102y?

p3. Find the number of positive factors of 37341337^3 \cdot 41^3.

Round 2

p4. Three hoses work together to fill up a pool, and each hose expels water at a constant rate. If it takes the first, second, and third hoses 4, 6, and 12 hours, respectively, to fill up the pool alone, then how long will it take to fill up the pool if all three hoses work together?

p5. A semicircle has radius 11. A smaller semicircle is inscribed in the larger one such that the two bases are parallel and the arc of the smaller is tangent to the base of the larger. An even smaller semicircle is inscribed in the same manner inside the smaller of the two semicircles, and this procedure continues indefinitely. What is the sum of all of the areas of the semicircles?

p6. Given that P(x)P(x) is a quadratic polynomial with P(1)=0P(1) = 0, P(2)=0P(2) = 0, and P(0)=2012P(0) = 2012, find P(1)P(-1).

Round 3

p7. Darwin has a paper circle. He labels one point on the circumference as AA. He folds AA to every point on the circumference on the circle and undoes it. When he folds AA to any point PP, he makes a blue mark on the point where AP\overline{AP} and the made crease intersect. If the area of Darwin paper circle is 80, then what is the area of the region surrounded by blue?

p8. Α rectangular wheel of dimensions 66 feet by 88 feet rolls for 2828 feet without sliding. What is the total distance traveled by any corner on the rectangle during this roll?

p9. How many times in a 2424-hour period do the minute hand and hour hand of a 1212-hour clock form a right angle?

Round 4

The answers in this section all depend on each other. Find smallest possible solution set.

p10. Let B be the answer to problem 1111. Right triangle ACDACD has a right angle at CC. Squares ACEFACEF and ADGHADGH are drawn such that points DD and EE do not coincide and points EE and HH do not coincide. The midpoints of the sides of ADGHADGH are connected to form a smaller square with area B.B. If the area of ACEFACEF is also BB, then find the length CDCD rounded up to the nearest integer.

p11. Let CC be the answer to problem 1212. Find the sum of the digits of CC.

p12. Let AA be the answer to problem 1010. Given that a0=1a_0 = 1, a1=2a_1 = 2, and that an=3an1an2a_n = 3a_{n-1 }-a_{n-2} for n2n \ge 2, find aAa_A.

PS. You should use hide for answers.Rounds 5-8 are here and 9-12 here. Collected here.

Solution

### Problem 1
1. The initial price of the TV is $100.
2. The price is increased by 10%, so the new price is:
100×1.1=110 100 \times 1.1 = 110
3. The new price is then decreased by 10%, so the current price is:
110×0.9=99 110 \times 0.9 = 99

Want a route through all this instead of an archive? The track puts 2,000 problems in a working order, from AMC 10 level to the IMO shortlist.

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic and difficulty added by this site.