3. Ana has been subscribed to a magazine for eight years. The subscription was $120 \mathrm{kn}$ in the first year. For the next six years, it increased by 4 kn annually. If Ana paid a total of 1084 kn over eight years, by how much did the subscription increase in the eighth year?
3. Ana has been subscribed to a magazine for eight years. The subscription was $120 \mathrm{kn}$ in the first year. For the next six years, it increased by 4 kn annually. If Ana paid a total of 1084 kn over eight years, by how much did the subscription increase in the eighth year?

## Solution.

The subscription was $120 \mathrm{kn}$ in the first year,

so it was $120+4=124 \mathrm{kn}$ in the second year, $124+4=128 \mathrm{kn}$ in the third year. \quad 1 POINT

It was $128+4=132 \mathrm{kn}$ in the fourth year, $132+4=136 \mathrm{kn}$ in the fifth year, \quad 1 POINT

$136+4=140 \mathrm{kn}$ in the sixth year, and $140+4=144 \mathrm{kn}$ in the seventh year. \quad 1 POINT

Over these seven years, she paid a total of $120+124+128+132+136+140+144=924 \mathrm{kn}$. \quad 1 POINT

This means the subscription in the eighth year was $1084 \mathrm{kn}-924 \mathrm{kn}=160 \mathrm{kn}$. \quad 1 POINT

In the eighth year, the subscription increased by $160-144=16$ kuna.

1 POINT

TOTAL 6 POINTS