Answer:
To calculate the fraction by which the income from sales decreases in August, we first need to calculate the total income from sales in July and August.
Let's assume that the laptop was sold at a price of $P in July, and the number of laptops sold was N.
So, the total income from sales in July would be I1 = P*N.
In August, the price of the laptop was 113% of P, which means the new price was (113/100)*P = 1.13P. Also, the number of laptops sold in August was 5 more than in July, which means the number of laptops sold in August was N+5.
So, the total income from sales in August would be I2 = 1.13P*(N+5) = 1.13PN + 5.65P.
Now, to find the fraction by which the income from sales decreases in August, we need to calculate the ratio of the income in August to the income in July:
I2/I1 = (1.13PN + 5.65P)/(PN) = 1.13 + 5.65/P.
The fraction by which the income from sales decreases in August is the difference between 1 and this ratio:
1 - (1.13 + 5.65/P) = (P - 1.13P - 5.65)/P = (0.87P - 5.65)/P.
So, the income from sales decreases in August by a fraction of (0.87P - 5.65)/P.