Problem No. 15. Jenn's blog

Jenn has a blog site. She started blogging on July 30 at 7.30 am. She is posting her posts at exactly 7 hours and 30 minutes apart. When will she post her 730th post?

Teacher tip

Suitable for practicing calendar calculations.

Problem No. 14. Two sisters

There have been two sisters. When the older sister was asked about their age, she said: "We had 730 months in total, 7 years and 30 months ago. Also, you have to know that I am 7 years and 30 months older than my sister." How old is each of the sisters?

Student tip

First find their age, 7 years and 30 months ago.

Problem No. 13. Sequence of numbers

Continue the following number sequence:

7, 3, 0, 3, 3, 6, 9, 5, …

Parent tip

Children love finding solutions together with their parents. Pretend that it is a difficult problem.

Problem No. 12. Sum of squares

Find all representations of the number 730 as a sum of two squares? And as a sum of three squares?

Teacher tip

Suitable for implementing the elimination and reminder methods while practicing the square numbers up to \(30^2\).

Problem No. 11. Urns and balls

There are 7 urns with 30 balls each. In each urn there is equal number of white and black balls. Randomly, we take out one ball from the first urn and put it into the second urn. Then, we take one ball from the second urn and put it into the third urn. We continue this process, until we take a ball from the seventh urn and put it into the first urn. Then, we take a ball from the first urn. What are the chances that the ball is black?

Student tip

First, find the probabilities for taking a black ball from each urn in first 7 steps.