## Search found 1175 matches

Sun Jan 30, 2011 9:26 am
Forum: Secondary: Solved
Topic: Dhaka Secondary 2011/7
Replies: 11
Views: 9062

### Re: Dhaka Secondary 2011/7

I don't think so!
Sat Jan 29, 2011 11:01 pm
Forum: Secondary: Solved
Topic: Dhaka Secondary 2011/9
Replies: 9
Views: 7703

### Re: Dhaka Secondary 2011/9

This one is really tricky,here is how I tamed it- Solution: We know that $2\equiv -1(mod 3) \Rightarrow2^x\equiv (-1)^x(mod 3)$ So we can strike out the numbers divisible by $3$. Now again the numbers which 'survive' are always like this- $x^2\equiv 1 (mod 3)$ So we have to just sum up the first \$20...
Sat Jan 29, 2011 10:49 pm
Forum: Secondary: Solved
Topic: Dhaka Secondary 2011/7
Replies: 11
Views: 9062

### Re: Dhaka Secondary 2011/7

Solution:
Sat Jan 29, 2011 10:43 pm
Forum: Secondary: Solved
Topic: Dhaka Secondary 2011/4
Replies: 2
Views: 2088

### Re: Dhaka Secondary 2011/4

Sat Jan 29, 2011 10:32 pm
Forum: Secondary: Solved
Topic: Dhaka Secondary 2011/1 (Higher Secondary 2011/1)
Replies: 9
Views: 8102

### Re: Dhaka Secondary 2011/1 (Higher Secondary 2011/1)

The answer isn't the one Tahmid posted,it is as follows- The answer is 76. Here we must know that in the silver ring set,there are 12 kinds,and in the gold ring set,there are 10 kinds.So at least 2 kinds of silver ring is different from the gold kinds.Now if we pick up 75 rings , all of them can be ...