Posted by **pooja** on Saturday, March 17, 2012 at 10:32am.

The diagram shows a spinner with six numbered sections.(where it has number 2 twice, # 1 triple & # 6 once )

Some of the sections are shaded.

Each time the spinner is spun it stops on one of the six sections.

It is equally likely that it stops on any one of the sections.

(a)The spinner is now spun twice. find the probability that the total of the 2 numbers is

(i)20 (ii) 11

(b)The spinner is now spun until it stops on a section numbered 2.

The probability that this happens on the nth spin is

16/243.

Find the value of n.

kindly show the steps

- maths-probability -
**Reiny**, Saturday, March 17, 2012 at 1:34pm
Since all you can get is 1, 2 or 6

there is no way to get a total of 20 or 11 with only 2 spins.

looks like either a typo or a flaw in the question.

2nd part.

Spin until you get a 2 ....

getting a 2 on

1 spin = (1/3)

2 spins = (2/3)(1/3) = 2^1 / 3^2

3 spins = (2/3)^2 (1/3) = 2^2 / 3^3

4 spins = (2/3)^3 (1/3) = 2^3 / 3^4

...

n spins = 2^(n-1) / 3^n

so 2^(n-1) / 3^n = 16/243

2^(n-1) / 3^n = 2^4 / 3^5

n = 5

## Answer This Question

## Related Questions

- Probability - The spinner has 6 sections 2 of which are 2. The spinner is now ...
- math - A spinner is divided into 5 equal sections numbered 1, 2, 3, 4, and 5. If...
- Algebra 2 - There are two spinners. Each spinner is numbered 1-4. Each spinner ...
- Math - My question: A spinner looks like this: A disc divided into sections that...
- Math (Probability) - I've worked out the first part of the question, just need ...
- Math. - A spinner is divided into 8 equal sections. There are 3 yellow sections ...
- Math - You roll a number cube numbered from 1 to 6. You then spin a spinner with...
- Pre-Algebra (Probability) - The theoretical probability of spinning an even ...
- ALGEBRA - A SPINNER WITH FOUR EQUAL SECTIONS NUMBERED 3,5,7 AND 8 IS SPUN TWICE...
- Math - Carol makes a spinner for a game. The spinner is divided into 10 equal ...

More Related Questions