I don't know how to prove this

I don't know how to prove this

The answer is 217 but I don't know the solution

Jay has 9 cupboards with the numbers 1 to 9 written. He has to form 3 three-digit numbers which are divisible by 9 with these cardboards and arrange them in ascending order. In how many different...

r => row of chairs x => total amount of chairs When you try to make 5 rows, there's 12 chairs left over. When you try to make 7 rows, there's 4 chairs too little. And...

NOTE THAT,the sequence doesn't matter.such that (1,2,3,4) and (1,3,2,4) are same

question is been relates to junior maths olympiad prectice test.for class 5

What is the least number that is divisible by 2, 3, 4, 5, 6, 8, 9 and 10?

Prove that (a + b + c)333 - a333 - b333 - c333 is divisible by (a + b + c)3 - a3 - b3 - c3 How can I start this? Thanks...

Let a, b, and c be integers with a≠0. Prove that if a|b and b|c then a|c.

I left my glasses at home so I couldn't quite see the number on the board. The first digit was a 7 and the last was a 4, but I couldn't make out the middle numbers. It was certainly a 4 digit number...

each digit can be used only once

Next year Charlie will be half the age of Gwen. Gwen will be 6 years older than Charlie next year. How old is Gwen this year?

Scott earned $35, $40, $40, $25, and $45 for 5 weeks of part-time work. During a school break, he worked-full-time for one week and earned $187. How much greater were his mean weekly earnings with...