# Task No. 8.1

## Condition:

Zebras Alex, Buffy, Web, and Gunya counted their stripes. During this, they had the following conversation.

Alex: “Gunya, Buffy, and I have 70 stripes together.”

Buffy: “I have twice as many stripes as Gunya.”

Gunya: “I have 2 more stripes than Alex.”

Web: “I have more stripes than Alex and Gunya together, but fewer than Buffy.”

How many stripes does Web have?
# Answer: 35

## Exact match of the answer -1 point

## Solution.

Let the number of stripes on the zebras of Alex, Buffy, Webby, and Gunya be A, B, V, and $\Gamma$ respectively. It is known that A+B+$\Gamma=70, B=2\Gamma, \Gamma=\mathrm{A}+2$, from the last two equations we get that $B=2\mathrm{A}+4$. Substituting B and $\Gamma$ into the first equation, we get $\mathrm{A}+2\mathrm{A}+4+\mathrm{A}+2=70$, from which $4\mathrm{A}=64, \mathrm{A}=16, \Gamma=18$ and B=36. Webby has more stripes than $\mathrm{A}+\Gamma=34$, but fewer than $\mathrm{B}=36$, so $\mathrm{B}=35$.

## Condition:

The zebras Alex, Buffy, Webby, and Gunya counted their stripes. In the process, they had the following conversation.

Alex: "I, Gunya, and Buffy together have 74 stripes."

Buffy: "I have twice as many stripes as Gunya."

Gunya: "I have 2 more stripes than Alex."

Webby: "I have more stripes than Alex and Gunya together, but fewer than Buffy."

How many stripes does Webby have?

Answer: 37

Exact match of the answer -1 point

Solution by analogy with problem 8.1

## Condition:

The zebras Alex, Buffy, Webby, and Gunya counted their stripes. In the process, they had the following conversation.

Alex: "I, Gunya, and Buffy together have 78 stripes."

Buffy: "I have twice as many stripes as Gunya."

Gunya: "I have 2 more stripes than Alex."

Webby: "I have more stripes than Alex and Gunya together, but fewer than Buffy."

How many stripes does Webby have?

Answer: 39

Exact match of the answer -1 point

Solution by analogy with problem 8.1

## Condition:

The zebras Alex, Buffy, Webby, and Gunya counted their stripes. In the process, they had the following conversation.

Alex: "I, Gunya, and Buffy together have 82 stripes."

Buffy: "I have twice as many stripes as Gunya."

Gunya: "I have 2 more stripes than Alex."

Webby: "I have more stripes than Alex and Gunya together, but fewer than Buffy."

How many stripes does Webby have?

Answer: 41

Exact match of the answer -1 point

Solution by analogy with problem 8.1