4. (7 points) The inflation index for the deposit period (year) will be $\mathrm{j}=\left(1+\mathrm{i}_{1}\right) \times\left(1+\mathrm{i}_{2}\right)$

Where: $\mathrm{i}_{1}$ and $\mathrm{i}_{2}$ are the inflation rates for the first and second halves of the deposit period, respectively, in fractions;

$\mathrm{j}=\left(1+\mathrm{i}_{1}\right) \times\left(1+\mathrm{i}_{2}\right)=(1+0.015) \times(1+0.02)=1.015 \times 1.02=1.0353$

The amount of Sasha's deposit with interest from the parents' gift before entering the 11th grade, in terms of its purchasing power (considering inflation), will be:

$\mathrm{H}_{\text {Ssumj }}=\mathrm{H}_{\text {Ssum }} / \mathrm{j}=268003 / 1.0353=258865$ rubles.

The amount of Kolya's deposit, considering inflation, will be:

$\mathrm{H}_{\text {Ksumj }}=\mathrm{H}_{\text {Ksum }} / \mathrm{j}=267875 / 1.0353=258741$ rubles.

Thus, the real income of the boys from the gift deposits from their parents, in terms of purchasing power (considering inflation), will be:

$\mathrm{D}=\mathrm{H}_{\text {sumj }}-\mathrm{V}$

Real income of Sasha:

$\mathrm{D}=\mathrm{H}_{\text {sumj }}-\mathrm{V}=258865-250000=8865$ rubles

Real income of Kolya:

$\mathrm{D}=\mathrm{H}_{\text {sumj }}-\mathrm{V}=258741-250000=8741$ rubles
Answer: 1. - 350600 rubles, 2. Sasha - 268003 rubles, Kolya - 267875 rubles, 3. Sasha has 128 rubles more, 4. Sasha's real income - 8865 rubles. Kolya's real income - 8741 rubles.

## Checking criteria:

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