To find out how many lawns Elliot needs to mow to afford the BMX bike, we can start by setting up the inequality.
Step 1: Write the Inequality
The total amount of money Elliot will have after mowing \( x \) lawns is $40 (what he has already earned) plus $20 for each lawn he mows:
\[ 40 + 20x \geq 218 \]
Step 2: Solve the Inequality
Now, we'll solve the inequality for \( x \).
- Subtract 40 from both sides:
\[ 20x \geq 218 - 40 \]
\[ 20x \geq 178 \]
- Divide both sides by 20:
\[ x \geq \frac{178}{20} \]
\[ x \geq 8.9 \]
Since \( x \) represents the number of lawns, and he can't mow a fraction of a lawn, we round up to the nearest whole number:
\[ x \geq 9 \]
Final Answer
Elliot needs to mow at least 9 lawns to earn enough money to buy the BMX bike.
The two parts are:
- The inequality used: \( 40 + 20x \geq 218 \)
- The minimum number of lawns he needs to mow: \( x \geq 9 \)