you are getting paid $15 for every lawn you mow.
But now you need to pay your parents 10%
You need $300 to buy a Switch how many lawns do you need to mow
Don't forget that the 10 percent you pay your parents is not your profit
To calculate the number of lawns you need to mow, first, calculate the amount you need to keep after paying your parents. Since you need $300 for a Switch and you need to pay your parents 10%, you will keep 90% of each payment.
Amount you keep = $15 x 90% = $15 x 0.9 = $13.50
Now, divide the total amount needed ($300) by the amount you keep per lawn ($13.50).
Number of lawns needed = $300 / $13.50 = 22.22
Since you cannot mow a fractional number of lawns, you will need to round up to the nearest whole number.
Therefore, you will need to mow at least 23 lawns to have enough money to buy a Switch after paying your parents.