1. For any two numbers a and b, a*b means $a+b-\frac{2011}{2}$.
Calculate: $1*2*3*...*2010*2011$.
ผมคิดว่าตอบ 2011 ครับ
2. Suppose 11 coconuts have the same cost as 14 pineapples, 22 mango have the same cost as 21 pineapples, 10 mango have the same cost as 3 bananas, and 5 oranges have the same cost as 2 bananas. How many coconuts have the same cost as 13 oranges?
ผมคิดว่าตอบ 13 ครับ
3. A girl calculates $\frac{1+2}{3}+\frac{4+5}{6}+...+\frac{2011+2012}{2013}$ and a boy calculates $1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{671}$. What is the sum of their answers?
ผมคิดว่าตอบ 1342 ครับ
4. What is the first time between 4:00 and 5:00 that the hour hand and the minute hand are exactly 10° apart?
ผมคิดว่าตอบ 4:20 ครับ
5. Two squirrels, Tim and Kim, are dividing a pile of hazelnuts. Tim starts by taking 5 hazelnuts. Thereafter, they take alternate turns, each time taking 1 more hazelnut than the other in the preceding turn. If the number of hazelnuts to be taken is larger than what remains in the pile, then all remaining hazelnuts are taken. At the end, Tim has taken 101 hazelnuts. What is the exact number of hazelnuts at the beginning?
ผมคิดว่าตอบ 215 ครับ
6. In how many ways can we pay a bill of 500 dollars by a combination of 10 dollar, 20 dollar and 50 dollar notes?
ผมคิดว่าตอบ 146 ครับ
7. The least common multiple of the numbers 16, 50 and A is 1200. How many positive integers A have this property?
ผมคิดว่าตอบ 15ครับ
8. In the figure below, $\frac{AM}{MB}=\frac{BN}{NC}=\frac{CP}{PA}=\frac{1}{2}$ and $\frac{MQ}{QN}=\frac{NR}{RP}=\frac{PS}{SM}=\frac{1}{2}$. If the area of $\bigtriangleup ABC$ is $360 cm^2$, what is the area of $\bigtriangleup QRS$, in $cm^2$?
ผมคิดว่าตอบ 40 ครับ
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