4. Bob bought 3 packs of model cars. He gave 4 cars to Ann. Bob has 11 cars left. How many model cars were in each pack?

Let's denote the number of model cars in each pack as \( x \). Since Bob bought 3 packs of model cars, the total number of model cars he had initially is \( 3x \). After giving 4 cars to Ann, Bob has 11 cars left. Therefore, the total number of model cars Bob had initially minus the 4 cars he gave to Ann is equal to 11. We can set up the equation based on this information: \[ 3x - 4 = 11 \] Now, we can solve for \( x \) to find out how many model cars were in each pack. Solve the equation by following steps: - step0: Solve for \(x\): \(3x-4=11\) - step1: Move the constant to the right side: \(3x=11+4\) - step2: Add the numbers: \(3x=15\) - step3: Divide both sides: \(\frac{3x}{3}=\frac{15}{3}\) - step4: Divide the numbers: \(x=5\) The solution to the equation is \( x = 5 \). Therefore, there were 5 model cars in each pack.